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openSUSE Leap 15.6

Start-Up

Publication Date: June 10, 2024
About this guide
Available documentation
Improving the documentation
Documentation conventions
Source code
Acknowledgments
I Installation
1 Installation Quick Start
1.1 Getting openSUSE Leap
1.2 Minimum system requirements
1.3 Installing openSUSE Leap
2 Boot parameters
2.1 Using the default boot parameters
2.2 PC (AMD64/Intel 64/AArch64)
2.3 List of important boot parameters
2.4 Advanced setups
2.5 More information
3 Installation steps
3.1 Overview
3.2 Installer self-update
3.3 Language, keyboard and license agreement
3.4 Network settings
3.5 Online repositories
3.6 System roles
3.7 Partitioning
3.8 Clock and time zone
3.9 Create new user
3.10 Authentication for the system administrator root
3.11 Installation settings
3.12 Performing the installation
4 Troubleshooting
4.1 Checking media
4.2 No bootable drive available
4.3 Booting from installation media fails
4.4 Boot failure
4.5 Graphical installer fails to start
4.6 Only minimal boot screen is displayed
II Administration
5 Managing users with YaST
5.1 User and group administration dialog
5.2 Managing user accounts
5.3 Additional options for user accounts
5.4 Changing default settings for local users
5.5 Assigning users to groups
5.6 Managing groups
5.7 Changing the user authentication method
5.8 Default system users
5.9 Default system groups
6 Changing language and country settings with YaST
6.1 Changing the system language
6.2 Changing the country and time settings
7 Printer operation
7.1 The CUPS workflow
7.2 Methods and protocols for connecting printers
7.3 Installing the software
7.4 Network printers
7.5 Configuring CUPS with command line tools
7.6 Printing from the command line
7.7 Special features in openSUSE Leap
7.8 Troubleshooting
8 Accessing file systems with FUSE
8.1 Configuring FUSE
8.2 Mounting an NTFS partition
8.3 Mounting remote file system with SSHFS
8.4 Mounting an ISO file system
8.5 Available FUSE plug-ins
8.6 More information
III Managing and updating software
9 Installing or removing software
9.1 Definition of terms
9.2 Using the YaST software manager
9.3 Managing software repositories and services
9.4 The GNOME package updater
9.5 Updating packages with GNOME Software
10 Installing add-on products
10.1 Add-ons
10.2 Binary drivers
11 YaST online update
11.1 The online update dialog
11.2 Installing patches
11.3 Viewing retracted patches
11.4 Automatic online update
12 Upgrading the system and system changes
12.1 Upgrading the system
12.2 More information
IV The Bash shell
13 Shell basics
13.1 Starting a shell
13.2 Entering commands
13.3 Getting help
13.4 Working with files and directories
13.5 Becoming root
13.6 File access permissions
13.7 Time-saving features of Bash
13.8 Editing texts
13.9 Searching for files or contents
13.10 Viewing text files
13.11 Redirection and pipes
13.12 Starting programs and handling processes
13.13 Archives and data compression
13.14 Important Linux commands
14 Bash and Bash scripts
14.1 What is the shell?
14.2 Writing shell scripts
14.3 Redirecting command events
14.4 Using aliases
14.5 Using variables in Bash
14.6 Grouping and combining commands
14.7 Working with common flow constructs
14.8 More information
V Hardware configuration
15 Setting up your system keyboard layout
16 Setting up sound cards
17 Setting up a printer
17.1 Configuring printers
17.2 Configuring printing via the network with YaST
17.3 Sharing printers over the network
18 Setting up a scanner
18.1 Configuring an HP all-in-one device
18.2 Sharing a scanner over the network
18.3 Scanning over the network
19 Persistent memory
19.1 Introduction
19.2 Terms
19.3 Use cases
19.4 Tools for managing persistent memory
19.5 Setting up persistent memory
19.6 More information
VI Help and troubleshooting
20 Help and documentation
20.1 Documentation directory
20.2 Man pages
20.3 Info pages
20.4 Online resources
21 Common problems and their solutions
21.1 Finding and gathering information
21.2 Boot problems
21.3 Login problems
21.4 Network problems
21.5 Data problems
A GNU licenses
A.1 GNU Free Documentation License

Copyright © 2006–2024 SUSE LLC and contributors. All rights reserved.

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or (at your option) version 1.3; with the Invariant Section being this copyright notice and license. A copy of the license version 1.2 is included in the section entitled GNU Free Documentation License.

For SUSE trademarks, see https://www.suse.com/company/legal/. All third-party trademarks are the property of their respective owners. Trademark symbols (®, ™ etc.) denote trademarks of SUSE and its affiliates. Asterisks (*) denote third-party trademarks.

All information found in this book has been compiled with utmost attention to detail. However, this does not guarantee complete accuracy. Neither SUSE LLC, its affiliates, the authors nor the translators shall be held liable for possible errors or the consequences thereof.

About this guide Edit source

This manual will see you through your initial contact with openSUSE® Leap. Learn how to install, use and enjoy your system.

Installation

Guides you through the installation process and the basic configuration of your system. The Quick Start section shows a quick walkthrough of the installation using default values. The second part of this chapter provides details for every installation step.

Administration

Introduces YaST, the central tool for installation and configuration of your system. Learn how to initially set up your system and how to modify key components of your system.

Managing and updating software

Understand how to install or remove software with either YaST or using the command line, how to use the 1-Click Install feature, and how to keep your system up-to-date.

The Bash shell

Learn how to work with the bash shell, the default command line interpreter on openSUSE Leap. Get to know the most commonly used Linux commands and understand basic concepts of a Linux system.

Help and troubleshooting

Provides an overview of where to find help and additional documentation in case you need more information or want to perform specific tasks with your system. Also find a compilation of the most frequent problems and annoyances and learn how to solve these problems on your own.

1 Available documentation Edit source

Online documentation

Our documentation is available online at https://doc.opensuse.org. Browse or download the documentation in various formats.

Note
Note: Latest updates

The latest updates are usually available in the English-language version of this documentation.

SUSE Knowledgebase

If you run into an issue, check out the Technical Information Documents (TIDs) that are available online at https://www.suse.com/support/kb/. Search the SUSE Knowledgebase for known solutions driven by customer need.

In your system

For offline use, the release notes are also available under /usr/share/doc/release-notes on your system. The documentation for individual packages is available at /usr/share/doc/packages.

Many commands are also described in their manual pages. To view them, run man, followed by a specific command name. If the man command is not installed on your system, install it with sudo zypper install man.

2 Improving the documentation Edit source

Your feedback and contributions to this documentation are welcome. The following channels for giving feedback are available:

Bug reports

Report issues with the documentation at https://bugzilla.opensuse.org/.

To simplify this process, click the Report an issue icon next to a headline in the HTML version of this document. This preselects the right product and category in Bugzilla and adds a link to the current section. You can start typing your bug report right away.

A Bugzilla account is required.

Contributions

To contribute to this documentation, click the Edit source document icon next to a headline in the HTML version of this document. This will take you to the source code on GitHub, where you can open a pull request.

A GitHub account is required.

Note
Note: Edit source document only available for English

The Edit source document icons are only available for the English version of each document. For all other languages, use the Report an issue icons instead.

For more information about the documentation environment used for this documentation, see the repository's README.

Mail

You can also report errors and send feedback concerning the documentation to <>. Include the document title, the product version, and the publication date of the document. Additionally, include the relevant section number and title (or provide the URL) and provide a concise description of the problem.

Help

If you need further help on openSUSE Leap, see https://en.opensuse.org/Portal:Support.

3 Documentation conventions Edit source

The following notices and typographic conventions are used in this document:

  • /etc/passwd: Directory names and file names

  • PLACEHOLDER: Replace PLACEHOLDER with the actual value

  • PATH: An environment variable

  • ls, --help: Commands, options, and parameters

  • user: The name of a user or group

  • package_name: The name of a software package

  • Alt, AltF1: A key to press or a key combination. Keys are shown in uppercase as on a keyboard.

  • File, File › Save As: menu items, buttons

  • Chapter 1, Example chapter: A cross-reference to another chapter in this guide.

  • Commands that must be run with root privileges. You can also prefix these commands with the sudo command to run them as a non-privileged user:

    # command
    > sudo command
  • Commands that can be run by non-privileged users:

    > command
  • Commands can be split into two or multiple lines by a backslash character (\) at the end of a line. The backslash informs the shell that the command invocation will continue after the end of the line:

    > echo a b \
    c d
  • A code block that shows both the command (preceded by a prompt) and the respective output returned by the shell:

    > command
    output
  • Notices

    Warning
    Warning: Warning notice

    Vital information you must be aware of before proceeding. Warns you about security issues, potential loss of data, damage to hardware, or physical hazards.

    Important
    Important: Important notice

    Important information you should be aware of before proceeding.

    Note
    Note: Note notice

    Additional information, for example about differences in software versions.

    Tip
    Tip: Tip notice

    Helpful information, like a guideline or a piece of practical advice.

  • Compact Notices

    Note

    Additional information, for example about differences in software versions.

    Tip

    Helpful information, like a guideline or a piece of practical advice.

4 Source code Edit source

The source code of openSUSE Leap is publicly available. Refer to https://en.opensuse.org/Source_code for download links and more information.

5 Acknowledgments Edit source

With a lot of voluntary commitment, the developers of Linux cooperate on a global scale to promote the development of Linux. We thank them for their efforts—this distribution would not exist without them. Special thanks, of course, goes to Linus Torvalds.

Part I Installation Edit source

1 Installation Quick Start

Use the following procedures to install a new version of openSUSE® Leap 15.6. This document gives a quick overview on how to run through a default installation of openSUSE Leap on the x86_64 architecture.

For more detailed installation instructions see Chapter 3, Installation steps. For installing the AArch64 and POWER variants, see https://en.opensuse.org/Portal:ARM and https://en.opensuse.org/Portal:PowerPC.

2 Boot parameters

openSUSE Leap allows setting several parameters during boot, for example choosing the source of the installation data or setting the network configuration.

3 Installation steps

This chapter describes the procedure in which the data for openSUSE Leap is copied to the target device. Some basic configuration parameters for the newly installed system are set during the procedure. A graphical user interface will guide you through the installation. The text mode installation has the same steps and only looks different. For information about performing non-interactive automated installations, see Book “AutoYaST Guide”.

4 Troubleshooting

This section covers several common installation problems and describes possible solutions.

1 Installation Quick Start Edit source

Abstract

Use the following procedures to install a new version of openSUSE® Leap 15.6. This document gives a quick overview on how to run through a default installation of openSUSE Leap on the x86_64 architecture.

For more detailed installation instructions see Chapter 3, Installation steps. For installing the AArch64 and POWER variants, see https://en.opensuse.org/Portal:ARM and https://en.opensuse.org/Portal:PowerPC.

1.1 Getting openSUSE Leap Edit source

To download openSUSE Leap, visit https://get.opensuse.org/leap/. On the Download tab you will find download links for different architectures:

  • Intel or AMD 64-bit desktops, laptops, and servers (AMD64/Intel 64)

  • UEFI Arm 64-bit servers, desktops, laptops and boards (AArch64)

  • PowerPC servers (little-endian, ppc64le)

  • IBM Z and IBM LinuxONE (IBM servers, s390x)

You also have the choice between two different images for download: Offline Image and Network Image. Check the documentation on the download page under Choosing Which Media to Download for more information.

Documentation on how to create a bootable installation media is also available on the download page under Easy Ways to Switch to openSUSE Leap.

1.2 Minimum system requirements Edit source

  • Any AMD64/Intel* EM64T processor (32-bit processors are not supported)

  • 1 GB physical RAM (at least 1.5 GB when using online repos, 4 GB or more strongly recommended)

  • 10 GB available disk space for a minimal installation, 16 GB for a graphical desktop (more is recommended). In case you plan to use Btrfs snapshots a minimum of 40 GB for the root partition is recommended.

  • Supports most modern sound and graphics cards, 1024 x 768 display resolution (higher recommended)

1.3 Installing openSUSE Leap Edit source

Use these instructions if there is no existing Linux system on your machine, or if you want to replace an existing Linux system.

1.3.1 Booting the installation system Edit source

Insert a DVD or a bootable USB stick containing the installation image for openSUSE Leap, then reboot the computer to start the installation program. On machines with a traditional BIOS you will see the graphical boot screen shown below. On machines equipped with UEFI, a slightly different boot screen is used. Secure boot on UEFI machines is supported.

On BIOS machines, use F2 to change the language for the installer. A corresponding keyboard layout is chosen automatically. See Section 2.2.1, “The boot screen on machines with traditional BIOS” or Section 2.2.2, “The boot screen on machines equipped with UEFI” for more information about changing boot parameters. On UEFI machines adjust the language and keyboard settings in the next step.

Select Installation on the boot screen, then press Enter. This boots the system and loads the openSUSE Leap installer.

1.3.2 Language, keyboard and license agreement Edit source

On systems with a traditional BIOS the Language and Keyboard Layout settings are initialized with the language you chose at the boot screen. If you did not change the default, or are using a UEFI machine it will be English (US). Change the settings here, if necessary. Use the Keyboard Test text box to test the layout.

Read the License Agreement. It is presented in the language you have chosen. Other License Translations are available. Proceed with Next.

1.3.3 Network settings Edit source

If the network can not be configured automatically, the Network Settings dialog opens. Choose a network interface from the list and configure it with Edit. Alternatively, Add an interface manually. See Section 3.4, “Network settings” and Book “Reference”, Chapter 13 “Basic networking”, Section 13.4 “Configuring a network connection with YaST” for more information. If you prefer to do an installation without network access, skip this step without making any changes and proceed with Next.

1.3.4 Online repositories Edit source

A system analysis is performed, where the installer probes for storage devices, and tries to find other installed systems. If a network connection with Internet access is available, you will be asked to activate the online repositories. Answer with Yes to proceed. In case you do not have Internet access, this step will be skipped.

The online repositories are official openSUSE package sources. They not only offer additional packages not included on the installation media, but also the update repositories containing security and bug fixes. Using the default selection is recommended. Add at least the Main Update Repository, because it makes sure the system is installed with the latest security patches.

You have the following choices:

  • The Main Repository contains open source software (OSS). Compared to the DVD installation media, it contains many additional software packages, among them many additional desktop systems.

  • The Update repository with updates from SUSE Linux Enterprise 15 and the Update repository from openSUSE Backports contain updates for the Main Repository. Choosing this repository is recommended for all installation scenarios.

  • The Non-OSS Repository contains packages with a proprietary software license. Choosing it is not required for installing a custom desktop system.

  • Select Update Repository (Non-OSS) if you enabled the Non-OSS Repository. It contains the respective updates and security fixes.

  • All other repositories are intended for experienced users and developers. Click on a repository name to get more information.

Confirm your selection with Next. Depending on your choice, you need to confirm one or more license agreements. Do so by choosing Next until you proceed to the System Role screen. Now choose Next to proceed.

1.3.5 System role Edit source

Choose a general software and system configuration with this step by selecting a desktop or server configuration.

For a desktop installation, choose between Desktop with KDE Plasma, Desktop with GNOME, Desktop with Xfce or Generic Desktop. KDE and Xfce are somewhat similar to Windows. GNOME offers an alternative, innovative environment. If you prefer an alternative to the KDE, GNOME, or Xfce desktops, choose Generic Desktop. You will be able to choose between the LXDE, MATE and others later in the installation process by selecting Software in the Installation Settings dialog.

If you are setting up a server, you probably do not need a graphical user interface. Choose Server (Text Mode) in this case. Alternatively, set up a server system with a read-only root partition and transactional updates by choosing Transactional Server. This selection also is a prerequisite for setting up openSUSE Kubic. See https://kubic.opensuse.org/blog/2018-04-04-transactionalupdates/ for more information on transactional updates.

You can also manually choose the software configuration for your system. Select Custom and then Next to get to the Software Selection and System Tasks dialog. Choose one or more patterns for installation. By clicking Details, you can select individual packages.

Tip
Tip: Release notes

From this point on, the Release Notes can be viewed from any screen during the installation process by selecting Release Notes.

1.3.6 Suggested partitioning Edit source

Define a partition setup for openSUSE Leap in this step. Review the partition setup proposed by the system. If necessary, change it. You have the following options:

Guided setup

Starts a wizard which lets you refine the partitioning proposal. Options available here depend on your system setup. In case it contains more than a single hard disk, you may choose which disk(s) to use and where to place the root partition. If the disk(s) already contain partitions, decide whether to remove or resize them.

In subsequent steps you may also add LVM support and disk encryption. You can change the file system for the root partition and decide whether to have a separate home partition or not.

Expert partitioner

Opens the Expert Partitioner described in Book “Reference”, Chapter 5 “Expert Partitioner”, Section 5.1 “Using the Expert Partitioner. This gives you full control over the partitioning setup and lets you create a custom setup. This option is intended for experts.

Note
Note: Separate home partition

The default proposal no longer suggests to create a separate partition for /home. The /home directory contains the user's data and personal configuration files. Placing it on a separate directory makes it easier to rebuild the system in the future, or allows to share it with different Linux installations on the same machine.

In case you want to change the proposal to create a separate partition for /home, choose Guided Setup and click Next until you reach the Filesystem Options screen. Check Propose Separate Home Partition. By default it will be formatted with XFS, but you can choose to use a different file system. Close the dialog by clicking Next again.

To accept the proposed setup without any changes, choose Next to proceed.

1.3.7 Clock and time zone Edit source

Select the clock and time zone to use in your system. To manually adjust the time or to configure an NTP server for time synchronization, choose Other Settings. See Section 3.8, “Clock and time zone” for detailed information. Proceed with Next.

1.3.8 Local user Edit source

To create a local user, type the first and last name in the User’s Full Name field, the login name in the Username field, and the password in the Password field.

The password should be at least eight characters long and should contain both uppercase and lowercase letters and numbers. The maximum length for passwords is 72 characters, and passwords are case-sensitive.

For security reasons it is also strongly recommended not to enable the Automatic Login. You should also not Use this Password for the System Administrator but rather provide a separate root password in the next installation step.

If you install on a system where a previous Linux installation was found, you may Import User Data from a Previous Installation. Click Choose User for a list of available user accounts. Select one or more user.

In an environment where users are centrally managed (for example by NIS or LDAP) you may want to skip the creation of local users. Select Skip User Creation in this case.

Proceed with Next.

1.3.9 Authentication for the System Administrator root Edit source

Provide a password for the system administrator account (called the root user).

You should never forget the root password! After you entered it here, the password cannot be retrieved. See Section 3.10, “Authentication for the system administrator root for more information. Proceed with Next.

Tip
Tip: Passwords and keyboard layout

It is recommended to only use US ASCII characters. In case of a system error or when you need to start your system in rescue mode, the keyboard may not be localized.

In case you would like to enable password-less authentication via SSH login, you can import a key via Import Public SSH Key. If you want to completely disable root login via password, upload a key only and do not provide a root password. A login as system administrator will only be possible via SSH using the respective keyin this case.

1.3.10 Installation settings Edit source

Use the Installation Settings screen to review and—if necessary—change several proposed installation settings. The current configuration is listed for each setting. To change it, click the headline. Some settings, such as firewall or SSH can directly be changed by clicking the respective links.

Important
Important: Remote access

Changes you can make here, can also be made later at any time from the installed system. However, if you need remote access directly after the installation, you have to adjust the Security settings.

Booting

This section shows the boot loader configuration. Changing the defaults is only recommended if really needed. Refer to Book “Reference”, Chapter 12 “The boot loader GRUB 2” for details.

Software

The default scope of software includes the base system and X Window with the selected desktop. Clicking Software opens the Software Selection and System Tasks screen, where you can change the software selection by selecting or deselecting patterns. Each pattern contains several software packages needed for specific functions (for example, Web and LAMP server or a print server). For a more detailed selection based on software packages to install, select Details to switch to the YaST Software Manager. See Chapter 9, Installing or removing software for more information.

Default systemd target

If you have chosen to install a desktop system, the system boots into the graphical target, with network, multiuser and display manager support. If you have not installed a desktop, the system boots into a login shell (Text Mode).

System

View detailed hardware information by clicking System. In the resulting screen you can also change Kernel Settings—see Section 3.11.7, “System for more information.

Security

The CPU Mitigations refer to kernel boot command line parameters for software mitigations that have been deployed to prevent CPU side-channel attacks. Click the highlighted entry to choose a different option. For details, see Book “Reference”, Chapter 12 “The boot loader GRUB 2” CPU Mitigations.

By default, the Firewall is enabled with all network interfaces configured for the public zone, where all ports are closed by default, ensuring maximum security. See Book “Security and Hardening Guide”, Chapter 23 “Masquerading and firewalls” for configuration details.

The SSH service is disabled by default, its port (22) is closed. Therefore logging in from remote is not possible by default. Click enable and open to toggle these settings.

Network configuration

Displays the current network configuration. Click Network Configuration to change the settings. For details, see Book “Reference”, Chapter 13 “Basic networking”, Section 13.4 “Configuring a network connection with YaST”.

1.3.11 Start the installation Edit source

After you have finalized the system configuration on the Installation Settings screen, click Install. Depending on your software selection you may need to agree to license agreements before the installation confirmation screen pops up. Up to this point no changes have been made to your system. After you click Install a second time, the installation process starts.

1.3.12 The installation process Edit source

During the installation, the progress is shown in detail on the Details tab. The openSUSE Leap Release Notes tab shows important information; reading them is recommended.

After the installation routine has finished, the computer is rebooted into the installed system. Log in and start YaST to fine-tune the system. If you are not using a graphical desktop or are working from remote, refer to Book “Reference”, Chapter 1 “YaST in text mode” for information on using YaST from a terminal.

2 Boot parameters Edit source

Abstract

openSUSE Leap allows setting several parameters during boot, for example choosing the source of the installation data or setting the network configuration.

Using the appropriate set of boot parameters helps simplify your installation procedure. Many parameters can also be configured later using the linuxrc routines, but using the boot parameters is easier. In some automated setups, the boot parameters can be provided with initrd or an info file.

The way the system is started for the installation depends on the architecture—system start-up is different for PC (AMD64/Intel 64) or mainframe, for example. If you install openSUSE Leap as a VM Guest on a KVM or Xen hypervisor, follow the instructions for the AMD64/Intel 64 architecture.

Note
Note: Boot options and boot parameters

The terms Boot Parameters and Boot Options are often used interchangeably. In this documentation, we mostly use the term Boot Parameters.

2.1 Using the default boot parameters Edit source

The boot parameters are described in detail in Chapter 3, Installation steps. Generally, selecting Installation starts the installation boot process.

If problems occur, use Installation—ACPI Disabled or Installation—Safe Settings. For more information about troubleshooting the installation process, refer to Chapter 4, Troubleshooting.

The menu bar at the bottom of the screen offers some advanced functionality needed in some setups. Using the function keys (F1 ... F12), you can specify additional options to pass to the installation routines without having to know the detailed syntax of these parameters (see Chapter 2, Boot parameters). A detailed description of the available function keys is available in Section 2.2.1, “The boot screen on machines with traditional BIOS”.

2.2 PC (AMD64/Intel 64/AArch64) Edit source

This section describes changing the boot parameters for AMD64, Intel 64 and AArch64.

2.2.1 The boot screen on machines with traditional BIOS Edit source

The boot screen displays several options for the installation procedure. Boot from Hard Disk boots the installed system and is selected by default. Select one of the other options with the arrow keys and press Enter to boot it. The relevant options are:

Installation

The normal installation mode. All modern hardware functions are enabled. In case the installation fails, see F5Kernel for boot parameters that disable potentially problematic functions.

Upgrade

Perform a system upgrade. For more information refer to Chapter 12, Upgrading the system and system changes.

More › Rescue System

Starts a minimal Linux system without a graphical user interface. For more information, see Section 21.5.2, “Using the rescue system”. This option is not available on Live CDs.

More › Boot Linux System

Boot a Linux system that is already installed. You will be asked from which partition to boot the system.

More › Check Installation Media

This option is only available when you install from media created from downloaded ISOs. In this case it is recommended to check the integrity of the installation medium. This option starts the installation system before automatically checking the media. In case the check was successful, the normal installation routine starts. If a corrupt media is detected, the installation routine aborts. Replace the broken medium and restart the installation process.

More › Memory Test

Tests your system RAM using repeated read and write cycles. Terminate the test by rebooting. For more information, see Section 4.4, “Boot failure”.

The Boot Screen on Machines with a Traditional BIOS
Figure 2.1: The boot screen on machines with a traditional BIOS

Use the function keys shown at the bottom of the screen to change the language, screen resolution, installation source or to add an additional driver from your hardware vendor:

F1Help

Get context-sensitive help for the active element of the boot screen. Use the arrow keys to navigate, Enter to follow a link, and Esc to leave the help screen.

F2Language

Select the display language and a corresponding keyboard layout for the installation. The default language is English (US).

F3Video Mode

Select various graphical display modes for the installation. By Default the video resolution is automatically determined using KMS (Kernel Mode Setting). If this setting does not work on your system, choose No KMS and, optionally, specify vga=ask on the boot command line to get prompted for the video resolution. Choose Text Mode if the graphical installation causes problems.

F4Source

Normally, the installation is performed from the inserted installation medium. Here, select other sources, like FTP or NFS servers, or configure a proxy server.

F5Kernel

If you encounter problems with the regular installation, this menu offers to disable a few potentially problematic functions. If your hardware does not support ACPI (advanced configuration and power interface) select No ACPI to install without ACPI support. No local APIC disables support for APIC (Advanced Programmable Interrupt Controllers) which may cause problems with some hardware. Safe Settings boots the system with the DMA mode (for CD/DVD-ROM drives) and power management functions disabled.

If you are not sure, try the following options first: Installation—ACPI Disabled or Installation—Safe Settings. Experts can also use the command line (Boot Options) to enter or change kernel parameters.

F6Driver

Press this key to notify the system that you have an optional driver update for openSUSE Leap. With File or URL, load drivers directly before the installation starts. If you select Yes, you are prompted to insert the update disk at the appropriate point in the installation process.

2.2.2 The boot screen on machines equipped with UEFI Edit source

UEFI (Unified Extensible Firmware Interface) is a new industry standard which replaces and extends the traditional BIOS. The latest UEFI implementations contain the Secure Boot extension, which prevents booting malicious code by only allowing signed boot loaders to be executed. See Book “Reference”, Chapter 14 “UEFI (Unified Extensible Firmware Interface)” for more information.

The boot manager GRUB 2, used to boot machines with a traditional BIOS, does not support UEFI, therefore GRUB 2 is replaced with GRUB 2 for EFI. If Secure Boot is enabled, YaST will automatically select GRUB 2 for EFI for installation. From an administrative and user perspective, both boot manager implementations behave the same and are called GRUB 2 in the following.

Tip
Tip: Using additional drivers with Secure Boot

When installing with Secure Boot enabled, you cannot load drivers that are not shipped with openSUSE Leap. This is also true of drivers shipped via SolidDriver, because their signing key is not trusted by default.

To load drivers not shipped with openSUSE Leap, do either of the following:

  • Before the installation, add the needed keys to the firmware database via firmware/system management tools.

  • Use a bootable ISO that will enroll the needed keys in the MOK list on the first boot.

For more information, see Book “Reference”, Chapter 14 “UEFI (Unified Extensible Firmware Interface)”, Section 14.1 “Secure boot”.

The boot screen displays several options for the installation procedure. Change the selected option with the arrow keys and press Enter to boot it. The relevant options are:

Installation

The normal installation mode. All modern hardware functions are enabled. In case the installation fails, see F5Kernel for boot parameters that disable potentially problematic functions.

Upgrade

Perform a system upgrade. For more information refer to Chapter 12, Upgrading the system and system changes.

More › Rescue System

Starts a minimal Linux system without a graphical user interface. For more information, see Section 21.5.2, “Using the rescue system”. This option is not available on Live CDs.

More › Boot Linux System

Boot a Linux system that is already installed. You will be asked from which partition to boot the system.

More › Check Installation Media

This option is only available when you install from media created from downloaded ISOs. In this case it is recommended to check the integrity of the installation medium. This option starts the installation system before automatically checking the media. In case the check was successful, the normal installation routine starts. If a corrupt media is detected, the installation routine aborts.

The Boot Screen on Machines with UEFI
Figure 2.2: The boot screen on machines with UEFI

GRUB 2 for EFI on openSUSE Leap does not support a boot prompt or function keys for adding boot parameters. By default, the installation will be started with American English and the boot media as the installation source. A DHCP lookup will be performed to configure the network. To change these defaults or to add boot parameters you need to edit the respective boot entry. Highlight it using the arrow keys and press E. See the on-screen help for editing hints (note that only an English keyboard is available now). The Installation entry will look similar to the following:

setparams 'Installation'

   set gfxpayload=keep
   echo 'Loading kernel ...'
   linuxefi /boot/x86_64/loader/linux splash=silent
   echo 'Loading initial ramdisk ...'
   initrdefi /boot/x86_64/loader/initrd

Add space-separated parameters to the end of the line starting with linuxefi. To boot the edited entry, press F10. If you access the machine via serial console, press Esc0. A complete list of parameters is available at https://en.opensuse.org/Linuxrc.

2.3 List of important boot parameters Edit source

This section contains a selection of important boot parameters.

2.3.1 General boot parameters Edit source

autoyast=URL

The autoyast parameter specifies the location of the autoinst.xml control file for automatic installation.

manual=<0|1>

The manual parameter controls whether the other parameters are only default values that still must be acknowledged by the user. Set this parameter to 0 if all values should be accepted and no questions asked. Setting autoyast implies setting manual to 0.

Info=URL

Specifies a location for a file from which to read additional options.

upgrade=<0|1>

To upgrade openSUSE Leap, specify Upgrade=1.

dud=URL

Load driver updates from URL.

Set dud=ftp://ftp.example.com/PATH_TO_DRIVER or dud=http://www.example.com/PATH_TO_DRIVER to load drivers from a URL. When dud=1 you will be asked for the URL during boot.

language=LANGUAGE

Set the installation language. Some supported values are cs_CZ, de_DE, es_ES, fr_FR, ja_JP, pt_BR, pt_PT, ru_RU, zh_CN, and zh_TW.

acpi=off

Disable ACPI support.

noapic

No logical APIC.

nomodeset

Disable KMS.

textmode=1

Start installer in text mode.

console=SERIAL_DEVICE[,MODE]

SERIAL_DEVICE can be an actual serial or parallel device (for example ttyS0) or a virtual terminal (for example tty1). MODE is the baud rate, parity and stop bit (for example 9600n8). The default for this setting is set by the mainboard firmware. If you do not see output on your monitor, try setting console=tty1. It is possible to define multiple devices.

2.3.2 Configuring the network interface Edit source

Important
Important: Configuring the network interface

The settings discussed in this section apply only to the network interface used during installation. Configure additional network interfaces in the installed system by following the instructions in Book “Reference”, Chapter 13 “Basic networking”, Section 13.6 “Configuring a network connection manually”.

The network will only be configured if it is required during the installation. To force the network to be configured, use the netsetup or ifcfg parameters.

netsetup=VALUE

netsetup=dhcp forces a configuration via DHCP. Set netsetup=-dhcp when configuring the network with the boot parameters hostip, gateway and nameserver. With the option netsetup=hostip,netmask,gateway,nameserver the installer asks for the network settings during boot.

ifcfg=INTERFACE[.VLAN]=[.try,]SETTINGS

INTERFACE can be * to match all interfaces or, for example, eth* to match all interfaces that start with eth. It is also possible to use MAC addresses as values.

Optionally, a VLAN can be set behind the interface name, separated by a period.

If SETTINGS is dhcp, all matching interfaces will be configured with DHCP. If you add the try option, configuration will stop when the installation repository can be reached via one of the configured interfaces.

Alternatively, you can use static configuration. With static parameters, only the first matching interface will be configured, unless you add the try option. This will configure all interfaces until the repository can be reached.

The syntax for the static configuration is:

ifcfg=*="IPS_NETMASK,GATEWAYS,NAMESERVERS,DOMAINS"

Each comma separated value can in turn contain a list of space character separated values. IPS_NETMASK is in the CIDR notation, for example 10.0.0.1/24. The quotes are only needed when using space character separated lists. Example with two name servers:

ifcfg=*="10.0.0.10/24,10.0.0.1,10.0.0.1 10.0.0.2,example.com"
Tip
Tip: Other networking parameters

The ifcfg boot parameter is very powerful and allows you to set almost all networking parameters. In addition to the parameters mentioned above, you can set values for all configuration options (comma separated) from /etc/sysconfig/network/ifcfg.template and /etc/sysconfig/network/config. The following example sets a custom MTU size on an interface otherwise configured via DHCP:

ifcfg=eth0=dhcp,MTU=1500
hostname=host.example.com

Enter the fully qualified host name.

domain=example.com

Domain search path for DNS. Allows you to use short host names instead of fully qualified ones.

hostip=192.168.1.2[/24]

Enter the IP address of the interface to configure. The IP can contain the subnet mask, for example hostip=192.168.1.2/24. This setting is only evaluated if the network is required during the installation.

gateway=192.168.1.3

Specify the gateway to use. This setting is only evaluated if the network is required during the installation.

nameserver=192.168.1.4

Specify the DNS server in charge. This setting is only evaluated if the network is required during the installation.

domain=example.com

Domain search path. This setting is only evaluated if the network is required during the installation.

2.3.3 Specifying the installation source Edit source

If you are not using DVD or USB flash drive for installation, specify an alternative installation source.

install=SOURCE

Specify the location of the installation source to use. Possible protocols are cd, hd, slp, nfs, smb (Samba/CIFS), ftp, tftp, http, and https. The default option is cd.

To install over an encrypted connection, use an https URL. If the certificate cannot be verified, disable certificate checking with the sslcerts=0 boot parameter.

If an http, https, ftp, tftp, or smb URL is given, you can authenticate by specifying the user name and password with the URL. Example:

install=https://USER:PASSWORD@SERVER/DIRECTORY/DVD1/

In case of a Samba or CIFS installation, you can also specify the domain that should be used:

install=smb://WORKDOMAIN;USER:PASSWORD@SERVER/DIRECTORY/DVD1/

To use cd, hd or slp, set them as the following example:

install=cd:/
install=hd:/?device=sda/PATH_TO_ISO
install=slp:/

2.3.4 Specifying remote access Edit source

Only one of the different remote control methods should be specified at a time. The different methods are: SSH, VNC, remote X server.

display_ip=IP_ADDRESS

Display_IP causes the installing system to try to connect to an X server at the given address.

Important
Important: X authentication mechanism

The direct installation with the X Window System relies on a primitive authentication mechanism based on host names. This mechanism is disabled on current openSUSE Leap versions. Installation with SSH or VNC is preferred.

vnc=1

Enables a VNC server during the installation.

vncpassword=PASSWORD

Sets the password for the VNC server.

ssh=1

ssh enables SSH installation.

ssh.password=PASSWORD

Specifies an SSH password for the root user during installation.

2.4 Advanced setups Edit source

To configure access to a local RMT or supportconfig server for the installation, you can specify boot parameters to set up these services during installation. The same applies if you need IPv6 support during the installation.

2.4.1 Using IPv6 for the installation Edit source

By default you can only assign IPv4 network addresses to your machine. To enable IPv6 during installation, enter one of the following parameters at the boot prompt:

Accept IPv4 and IPv6
ipv6=1
Accept IPv6 only
ipv6only=1

2.4.2 Using a proxy for the installation Edit source

In networks enforcing the usage of a proxy server for accessing remote web sites, registration during installation is only possible when configuring a proxy server.

On systems with traditional BIOS, press F4 on the boot screen and set the required parameters in the HTTP Proxy dialog.

On Systems with UEFI BIOS, provide the boot parameter proxy at the boot prompt:

  1. On the boot screen, press E to edit the boot menu.

  2. Append the proxy parameter to the linux line in the following format:

    proxy=https://proxy.example.com:PORT

    If the proxy server requires authentication, add the credentials as follows:

    proxy=https://USER:PASSWORD@proxy.example.com:PORT

    If the proxy server's SSL certificate cannot be verified, disable certificate checking with the sslcerts=0 boot parameter.

    The outcome will be similar to the following:

    GRUB options editor
    Figure 2.3: GRUB options editor
  3. Press F10 to boot with the new proxy setting.

2.4.3 Enabling SELinux support Edit source

Enabling SELinux upon installation start-up enables you to configure it after the installation has been finished without having to reboot. Use the following parameters:

security=selinux selinux=1

2.4.4 Enabling the installer self-update Edit source

During installation and upgrade, YaST can update itself as described in Section 3.2, “Installer self-update” to solve potential bugs discovered after release. The self_update parameter can be used to modify the behavior of this feature.

To enable the installer self-update, set the parameter to 1:

self_update=1

To use a user-defined repository, specify a URL:

self_update=https://updates.example.com/

2.4.5 Reusing LVM Edit source

As of SUSE Linux Enterprise 15 SP6, the installer no longer reuses pre-existing Logical Volume Manager (LVM) configurations in its Guided Setup for this can be confusing and lead to suboptimal setups. To reuse an existing LVM regardless, use the YAST_REUSE_LVM parameter or configure it manually in the Expert Partitioner (Book “Reference”, Chapter 5 “Expert Partitioner).

2.4.6 Scale user interface for high DPI Edit source

If your screen uses a very high DPI, use the boot parameter QT_AUTO_SCREEN_SCALE_FACTOR. This scales font and user interface elements to the screen DPI.

QT_AUTO_SCREEN_SCALE_FACTOR=1

2.4.7 Using CPU mitigations Edit source

The boot parameter mitigations lets you control mitigation options for side-channel attacks on affected CPUs. Its possible values are:

auto Enables all mitigations required for your CPU model, but does not protect against cross-CPU thread attacks. This setting may impact performance to some degree, depending on the workload.

nosmt Provides the full set of available security mitigations. Enables all mitigations required for your CPU model. In addition, it disables Simultaneous Multithreading (SMT) to avoid side-channel attacks across multiple CPU threads. This setting may further impact performance, depending on the workload.

off Disables all mitigations. Side-channel attacks against your CPU are possible, depending on the CPU model. This setting has no impact on performance.

Each value comes with a set of specific parameters, depending on the CPU architecture, the kernel version, and on the vulnerabilities that need to be mitigated. Refer to the kernel documentation for details.

2.4.8 LUKS 2 Support Edit source

LUKS2 encryption is supported by the YaST installer as of SUSE Linux Enterprise 15 SP4, but needs to be enabled explicitly.

YAST_LUKS2_AVAILABLE

Alternatively, you can also enable LUKS2 in the YaST expert console. For more information, refer to Book “Reference”, Chapter 5 “Expert Partitioner”, Section 5.2 “Device encryption”.

2.5 More information Edit source

You can find more information about boot parameters in the openSUSE wiki at https://en.opensuse.org/SDB:Linuxrc#Parameter_Reference.

3 Installation steps Edit source

Abstract

This chapter describes the procedure in which the data for openSUSE Leap is copied to the target device. Some basic configuration parameters for the newly installed system are set during the procedure. A graphical user interface will guide you through the installation. The text mode installation has the same steps and only looks different. For information about performing non-interactive automated installations, see Book “AutoYaST Guide”.

If you are a first-time user of openSUSE Leap, you should follow the default YaST proposals in most parts, but you can also adjust the settings as described here to fine-tune your system according to your preferences. Help for each installation step is provided by clicking Help.

Tip
Tip: Installation without a mouse

If the installer does not detect your mouse correctly, use →| for navigation, arrow keys to scroll, and Enter to confirm a selection. Various buttons or selection fields contain a letter with an underscore. Use AltLetter to select a button or a selection directly instead of navigating there with →|.

3.1 Overview Edit source

This section provides an overview of all installation steps. Each step contains a link to a more detailed description.

  1. Before the installation starts, the installer may update itself. For details, see Section 3.2, “Installer self-update”.

  2. The actual installation starts with choosing the language and accepting the license agreement. For details, see Section 3.3, “ Language, keyboard and license agreement.

  3. Configure the network. This is only required when you need network access during the installation, and automatic network configuration via DHCP fails. If the automatic network configuration succeeds, this step is skipped. For details, see Section 3.4, “Network settings”.

  4. Configure the online repositories. By adding official openSUSE repositories, you get access to more software and get the latest security updates already during installation. For details, see Section 3.5, “Online repositories”. This step is optional and can be skipped.

  5. Select a desktop or a role for your system. This defines the default list of packages to install and makes a suggestion for partitioning the hard disks. For details, see Section 3.6, “System roles”.

  6. Partition the hard disks of your system. For details, see Section 3.7, “Partitioning”.

  7. Choose a time zone. For details, see Section 3.8, “Clock and time zone”.

  8. Create a user. For details, see Section 3.9, “Create new user”.

  9. (Optional) Optionally, set a different password for the system administrator root. For details, see Section 3.10, “Authentication for the system administrator root.

  10. In a final step, the installer presents an overview of all settings. If required, you can change them. For details, see Section 3.11, “Installation settings”.

  11. The installer copies all required data and informs you about the progress. For details, see Section 3.12, “Performing the installation”.

3.2 Installer self-update Edit source

During the installation and upgrade process, YaST may update itself to solve bugs in the installer that were discovered after the release. This functionality is enabled by default; to disable it, set the boot parameter self_update to 0. For more information, see Section 2.4.4, “Enabling the installer self-update”.

Important
Important: Networking during self-update

To download installer updates, YaST needs network access. By default, it tries to use DHCP on all network interfaces. If there is a DHCP server in the network, it will work automatically.

If you need a static IP setup, you can use the ifcfg boot argument. For more details, see the linuxrc documentation at https://en.opensuse.org/Linuxrc.

Tip
Tip: Language selection

The installer self-update runs before the language selection step. This means that progress and errors which happen during this process are displayed in English by default.

To use another language for this part of the installer, use the language boot parameter if available for your architecture, for example, language=de_DE. On machines equipped with a traditional BIOS, alternatively, press F2 in the boot menu and select the language from the list.

Although this feature was designed to run without user intervention, it is worth knowing how it works. If you are not interested, you can jump directly to Section 3.3, “ Language, keyboard and license agreement and skip the rest of this section.

3.2.1 Self-update process Edit source

The process can be broken down into two different parts:

  1. Determine the update repository location.

  2. Download and apply the updates to the installation system.

3.2.1.1 Determining the update repository location Edit source

Installer Self-Updates are distributed as regular RPM packages via a dedicated repository, so the first step is to find the repository URL.

Important
Important: Installer self-update repository only

No matter which of the following options you use, only the installer self-update repository URL is expected, for example:

self_update=https://www.example.com/my_installer_updates/

Do not supply any other repository URL—for example the URL of the software update repository.

YaST will try the following sources of information:

  1. The self_update boot parameter. (For more details, see Section 2.4.4, “Enabling the installer self-update”.) If you specify a URL, it will take precedence over any other method.

  2. The /general/self_update_url profile element in case you are using AutoYaST.

  3. If none of the previous attempts work, the fallback URL (defined in the installation media) will be used.

3.2.1.2 Downloading and applying the updates Edit source

When the update repository is determined, YaST checks whether an update is available. If it is, all the updates are downloaded and applied.

Finally, YaST restarts and displays the welcome screen. If no updates are available, the installation continues without restarting YaST.

Note
Note: Update integrity

Update signatures will be checked to ensure integrity and authorship. If a signature is missing or invalid, you will be asked whether you want to apply the update.

3.2.1.3 Temporary self-update add-on repository Edit source

Some packages distributed in the self-update repository provide additional data for the installer, like installation defaults, system role definitions and similar. If the installer finds such packages in the self-update repository, a local temporary repository is created, to which those packages are copied. They are used during the installation. The temporary local repository is removed at the end of the installation. Its packages are not installed on the target system.

This additional repository is not displayed in the list of add-on products, but during installation it may still be visible as SelfUpdate0 repository in the package management.

3.2.2 Custom self-update repositories Edit source

YaST can use a user-defined repository instead of the official repository by specifying a URL through the self_update boot parameter.

  • HTTP/HTTPS and FTP repositories are supported.

  • Starting with yast2-installation-4.4.30, the relurl:// schema is supported, as a boot parameter or in an AutoYaST profile. The URL is relative to the main installation repository, and you may navigate the file tree with the usual ../ notation, for example relurl://../self_update. This is useful when serving the packages via a local installation server, or when building a custom installation medium which includes a self-update repository.

    The following examples assume the installation repository is at the medium root (/), and the self-update repository in the self_update subdirectory. This structure makes the relurl:// portable, and it will work anywhere without changes as a boot parameter, copied to a USB stick, hard disk, network server, or in an AutoYaST profile.

    Custom DVD/USB medium

    Add the self_update=relurl://self_update boot option directly to the default boot parameters, and it will work properly even if the medium is copied to an USB stick, hard disk, or a network server.

    Installation server

    Assume that the installation packages are available via http://example.com/repo and a self-update repository is available at http://example.com/self_update.

    Then you can use the http://example.com/repo and http://example.com/self_update boot parameters, without having to change the self_update parameter when the repositories are moved to a different location.

  • Only RPM-MD repositories are supported (required by RMT).

  • Packages are not installed in the usual way: They are uncompressed only and no scripts are executed.

  • No dependency checks are performed. Packages are installed in alphabetical order.

  • Files from the packages override the files from the original installation media. This means that the update packages might not need to contain all files, only files that have changed. Unchanged files are omitted to save memory and download bandwidth.

Note
Note: Only one repository

Currently, it is not possible to use more than one repository as source for installer self-updates.

3.3 Language, keyboard and license agreement Edit source

Language, keyboard and product selection
Figure 3.1: Language, keyboard and license agreement

The Language and Keyboard Layout settings are initialized with the language you chose on the boot screen. If you did not change the default, it will be English (US). Change the settings here, if necessary.

Changing the language automatically selects a corresponding keyboard layout. You can override this proposal by selecting a different keyboard layout from the drop-down box. Use the Keyboard Test text box to test the layout. The selected language also determines a time zone for the system clock. This setting can be modified later as described in Chapter 6, Changing language and country settings with YaST.

Read the license agreement. It is presented in the language you have. Translations are available via the License Language drop-down box. Proceed with Next if you agree to the terms and conditions. If you do not agree, click Abort to terminate the installation.

Tip
Tip: Light and high-contrast themes

If you have difficulties reading the labels in the installer, you can change the widget colors and theme.

Click the Change the widget theme button or press ShiftF3 to open a theme selection dialog. Select a theme from the list and Close the dialog.

ShiftF4 switches to the color scheme for vision-impaired users. Press the buttons again to switch back to the default scheme.

3.4 Network settings Edit source

After booting into the installation, the installation routine is set up. During this setup, an attempt to configure at least one network interface with DHCP is made. In case this attempt has failed, the Network Settings dialog launches now.

Network Settings
Figure 3.2: Network settings

Choose a network interface from the list and click Edit to change its settings. Use the tabs to configure DNS and routing. See Book “Reference”, Chapter 13 “Basic networking”, Section 13.4 “Configuring a network connection with YaST” for more details.

In case DHCP was successfully configured during installation setup, you can also access this dialog by clicking Network Configuration at the the Installation Settings step. It lets you change the automatically provided settings.

Note
Note: Network configuration with boot parameters

If at least one network interface has been configured via boot parameters (see Section 2.3.2, “Configuring the network interface”), automatic DHCP configuration is disabled and the boot parameter configuration is imported and used.

Tip
Tip: Accessing network storage or local RAID

To access a SAN or a local RAID during the installation, you can use the libstorage command line client for this purpose:

  1. Switch to a console with CtrlAltF2.

  2. Install the libstoragemgmt extension by running extend libstoragemgmt.

  3. Now you have access to the lsmcli command. For more information, run lsmcli --help.

  4. To return to the installer, press AltF7

Supported are Netapp Ontap, all SMI-S compatible SAN providers, and LSI MegaRAID.

3.5 Online repositories Edit source

A system analysis is performed, where the installer probes for storage devices, and tries to find other installed systems. If a network connection with Internet access is available, you will be asked to activate the online repositories. Answer with Yes to proceed. In case you do not have Internet access, this step will be skipped.

The online repositories are official openSUSE package sources. They not only offer additional packages not included on the installation media, but also the update repositories containing security and bug fixes. Using the default selection is recommended. Add at least the Main Update Repository, because it makes sure the system is installed with the latest security patches.

You have the following choices:

  • The Main Repository contains open-source software (OSS). Compared to the DVD installation media, it contains many additional software packages, among them many additional desktop systems.

  • The Update repository with updates from SUSE Linux Enterprise 15 and the Update repository from openSUSE Backports contain updates for the Main Repository. Enabling these repositories is recommended for all installation scenarios.

  • The Non-OSS Repository contains packages with a proprietary software license. Enabling it is not required for installing a custom desktop system.

  • Enabling Update Repository (Non-OSS) is recommended if the Non-OSS Repository is enabled. This repository contains updates and security fixes for proprietary software.

  • All other repositories are intended for experienced users and developers. Click on a repository name to get more information.

Confirm your selection with Next. Depending on your choice, you need to confirm one or more license agreements. Do so by choosing Next until you proceed to the System Role screen. Now choose Next to proceed.

3.6 System roles Edit source

To simplify the installation, the installer offers predefined use cases that tailor the system for the selected scenario.

System Role
Figure 3.3: System role

Choose the System Role that meets your requirements best. The availability of system roles depends on your selection of modules and extensions. The dialog is omitted under the following conditions:

  • The combination of base product and modules does not allow roles to be chosen.

  • The combination of base product and modules only allows a single role.

With the default selection, the following system roles are available:

Desktop with KDE Plasma

A powerful desktop environment with a complete PIM suite (mail, calendar, tasks, notes, and feeds), widgets running on the desktop and many more features. If you are familiar with Windows, KDE is the recommended choice. For more information see https://kde.org/.

Desktop with GNOME

A desktop environment offering an alternative, innovative user experience. GNOME was designed with usability and productivity in mind. For more information see https://www.gnome.org/.

Desktop with Xfce

A lightweight traditional desktop environment. For more information, see https://www.xfce.org/.

Generic Desktop

In case you prefer an alternative to the KDE, GNOME, or Xfce desktops, choose this option. You will be able to choose between the following alternatives later in the installation process by selecting Software in the Installation Settings dialog:

Enlightenment (https://www.enlightenment.org/)
LXDE (https://lxde.org/)
LXQT (https://lxqt.org/)
MATE (https://mate-desktop.org/)

When installing from the DVD image, these desktop systems are only available if you enabled the Main Repository (OSS) in the Online Repositories step. You can still enable this repository at later points during the installation by using the Back button until you reach the welcome screen. From there, choose Next and then agree to add online repositories.

Server

If setting up a server, you probably do not need a graphical user interface and desktop applications such as an office suite. This option gives you a reduced set of packages suitable for servers.

Transactional Server

Similar to the server role, but with a read-only root partition and transactional updates. This selection also is a prerequisite for setting up openSUSE Kubic. See https://kubic.opensuse.org/blog/2018-04-04-transactionalupdates/ for more information on transactional updates.

3.7 Partitioning Edit source

3.7.1 Important information Edit source

Warning
Warning: Read this section carefully

Read this section carefully before continuing with Section 3.7.2, “Suggested partitioning”.

Custom partitioning on UEFI machines

A UEFI machine requires an EFI system partition that must be mounted to /boot/efi. This partition must be formatted with the FAT32 file system.

If an EFI system partition is already present on your system (for example from a previous Windows installation) use it by mounting it to /boot/efi without formatting it.

If no EFI system partition is present on your UEFI machine, make sure to create it. The EFI system partition must be a physical partition or RAID 1. Other RAID levels, LVM and other technologies are not supported. It needs to be formatted with the FAT32 file system.

Custom partitioning and Snapper

If the root partition is larger than 16 GB, openSUSE Leap by default enables file system snapshots.

openSUSE Leap uses Snapper together with Btrfs for this feature. Btrfs needs to be set up with snapshots enabled for the root partition.

If the disk is smaller than 16 GB, all Snapper features and automatic snapshots are disabled to prevent the system partition / from running out of space.

Being able to create system snapshots that enable rollbacks requires important system directories to be mounted on a single partition, for example /usr and /var. Only directories that are excluded from snapshots may reside on separate partitions, for example /usr/local, /var/log, and /tmp.

If snapshots are enabled, the installer will automatically create single snapshots during and immediately after the installation.

For details, see Book “Reference”, Chapter 3 “System recovery and snapshot management with Snapper”.

Important
Important: Btrfs snapshots and root partition size

Snapshots may take considerable storage space. Generally, the older a snapshot is or the larger the changeset it covers, the more storage space the snapshot takes. And the more snapshots you keep, the more disk space you need.

To prevent the root partition running full with snapshot data, you need to make sure it is big enough. In case you do frequent updates or other installations, consider at least 30 GB for the root partition. If you plan to keep snapshots activated for a system upgrade (to be able to roll back), you should consider 40 GB or more.

Btrfs data volumes

Using Btrfs for data volumes is supported on openSUSE Leap 15.6. For applications that require Btrfs as a data volume, consider creating a separate file system with quota groups disabled. This is already the default for non-root file systems.

Btrfs on an encrypted root partition

The default partitioning setup suggests the root partition as Btrfs. To encrypt the root partition, make sure to use the GPT partition table type instead of the MSDOS type. Otherwise the GRUB2 boot loader may not have enough space for the second stage loader.

Supported software RAID volumes

Installing to and booting from existing software RAID volumes is supported for Disk Data Format (DDF) volumes and Intel Matrix Storage Manager (IMSM) volumes. IMSM is also known by the following names:

Mount points for FCoE and iSCSI devices

FCoE and iSCSI devices will appear asynchronously during the boot process. While the initrd guarantees that those devices are set up correctly for the root file system, there are no such guarantees for any other file systems or mount points like /usr. Hence any system mount points like /usr or /var are not supported. To use those devices, ensure correct synchronization of the respective services and devices.

Handling of Windows partitions in proposals

In case the disk selected for the suggested partitioning proposal contains a large Windows FAT or NTFS partition, it will automatically be resized to make room for the openSUSE Leap installation. To avoid data loss it is strongly recommended to

  • make sure the partition is not fragmented (run a defragmentation program from Windows prior to the openSUSE Leap installation)

  • double-check the suggested size for the Windows partition is big enough

  • back up your data prior to the openSUSE Leap installation

To adjust the proposed size of the Windows partition, use the Expert Partitioner.

Proposal with a separate home partition

The default proposal no longer suggests to create a separate partition for /home. The /home directory contains the user's data and personal configuration files. Placing it on a separate directory makes it easier to rebuild the system in the future, or allows to share it with different Linux installations on the same machine.

In case you want to change the proposal to create a separate partition for /home, choose Guided Setup and click Next until you reach the Filesystem Options screen. Check Propose Separate Home Partition. By default it will be formatted with XFS, but you can choose to use a different file system. Close the dialog by clicking Next again.

3.7.2 Suggested partitioning Edit source

Define a partition setup for openSUSE Leap in this step.

Suggested Partitioning
Figure 3.4: Suggested partitioning

The installer creates a proposal for one of the available disks containing a root partition formatted with Btrfs and a swap partition. If one or more swap partitions have been detected on the available hard disks, these partitions will be used. You have several options to proceed:

Next

To accept the proposal without any changes, click Next to proceed with the installation workflow.

Guided setup

To adjust the proposal, choose Guided Setup. First, choose which hard disks and partitions to use. In the Partitioning Scheme screen, you can enable Logical Volume Management (LVM) and activate disk encryption. Afterward specify the Filesystem Options. You can adjust the file system for the root partition and create a separate home and swap partitions. If you plan to suspend your machine, make sure to create a separate swap partition and check Enlarge to RAM Size for Suspend. If the root file system format is Btrfs, you can also enable or disable Btrfs snapshots here.

Expert Partitioner

To create a custom partition setup click Expert Partitioner. Select either Start with Current Proposal if you want start with the suggested disk layout, or Start with Existing Partitions to ignore the suggested layout and start with the existing layout on the disk. You can Add, Edit, Resize, or Delete partitions.

You can also set up logical volume management (LVM), configure software RAID and device mapping (DM), encrypt partitions, mount NFS shares and manage tmpfs volumes with the Expert Partitioner. To fine-tune settings such as the subvolume and snapshot handling for each Btrfs partition, choose Btrfs. For more information about custom partitioning and configuring advanced features, refer to Book “Reference”, Chapter 5 “Expert Partitioner”, Section 5.1 “Using the Expert Partitioner.

Warning
Warning: Disk space units

Note that for partitioning purposes, disk space is measured in binary units, rather than in decimal units. For example, if you enter sizes of 1GB, 1GiB or 1G, they all signify 1 GiB (Gibibyte), as opposed to 1 GB (Gigabyte).

Binary

1 GiB = 1 073 741 824 bytes.

Decimal

1 GB = 1 000 000 000 bytes.

Difference

1 GiB ≈ 1.07 GB.

3.8 Clock and time zone Edit source

In this dialog, select your region and time zone. Both are preselected according to the installation language.

Clock and Time Zone
Figure 3.5: Clock and time zone

To change the preselected values, either use the map or the drop-down boxes for Region and Time Zone. When using the map, point the cursor at the rough direction of your region and left-click to zoom. Now choose your country or region by left-clicking. Right-click to return to the world map.

To set up the clock, choose whether the Hardware Clock is Set to UTC. If you run another operating system on your machine, such as Microsoft Windows, it is likely your system uses local time instead. If you run Linux on your machine, set the hardware clock to UTC and have the switch from standard time to daylight saving time performed automatically.

Important
Important: Set the hardware clock to UTC

The switch from standard time to daylight saving time (and vice versa) can only be performed automatically when the hardware clock (CMOS clock) is set to UTC. This also applies if you use automatic time synchronization with NTP, because automatic synchronization will only be performed if the time difference between the hardware and system clock is less than 15 minutes.

Since a wrong system time can cause serious problems (missed backups, dropped mail messages, mount failures on remote file systems, etc.), it is strongly recommended to always set the hardware clock to UTC.

If a network is already configured, you can configure time synchronization with an NTP server. Click Other Settings to either alter the NTP settings or to Manually set the time. See Book “Reference”, Chapter 18 “Time synchronization with NTP” for more information on configuring the NTP service. When finished, click Accept to continue the installation.

If running without NTP configured, consider setting SYSTOHC=no (sysconfig variable) to avoid saving unsynchronized time into the hardware clock.

3.9 Create new user Edit source

Create a local user in this step.

Create New User
Figure 3.6: Create new user

After entering the first name and last name, either accept the proposal or specify a new User name that will be used to log in. Only use lowercase letters (a-z), digits (0-9) and the characters . (dot), - (hyphen) and _ (underscore). Special characters, umlauts and accented characters are not allowed.

Finally, enter a password for the user. Re-enter it for confirmation (to ensure that you did not type something else by mistake). To provide effective security, a password should be at least six characters long and consist of uppercase and lowercase letters, numbers and special characters (7-bit ASCII). Umlauts or accented characters are not allowed. Passwords you enter are checked for weakness. When entering a password that is easy to guess (such as a dictionary word or a name) you will see a warning. It is a good security practice to use strong passwords.

Important
Important: User name and password

Remember both your user name and the password because they are needed each time you log in to the system.

If you install openSUSE Leap on a machine with one or more existing Linux installations, YaST allows you to import user data such as user names and passwords. Select Import User Data from a Previous Installation and then Choose Users for import.

If you do not want to configure any local users (for example when setting up a client on a network with centralized user authentication), skip this step by choosing Next and confirming the warning. Network user authentication can be configured at any time later in the installed system; refer to Chapter 5, Managing users with YaST for instructions.

Two additional options are available:

Use this password for system administrator

If checked, the same password you have entered for the user will be used for the system administrator root. This option is suitable for stand-alone workstations or machines in a home network that are administrated by a single user. When not checked, you are prompted for a system administrator password in the next step of the installation workflow (see Section 3.10, “Authentication for the system administrator root).

Automatic login

This option automatically logs the current user in to the system when it starts. This is mainly useful if the computer is operated by only one user.

Warning
Warning: Automatic login

With the automatic login enabled, the system boots straight into your desktop with no authentication. If you store sensitive data on your system, you should not enable this option if the computer can also be accessed by others.

In an environment where users are centrally managed (for example by NIS or LDAP) you should skip the creation of local users. Select Skip User Creation in this case.

3.10 Authentication for the system administrator root Edit source

If you have not chosen Use this Password for System Administrator in the previous step, you will be prompted to enter a password for the system administrator root or provide a public SSH key. Otherwise, this configuration step is skipped.

Authentication for the System Administrator root
Figure 3.7: Authentication for the system administrator root

Enter the password for the system administrator root. For verification purposes, the password for root must be entered twice. Do not forget the password as it cannot be retrieved later.

Tip
Tip: Passwords and keyboard layout

It is recommended to only use US ASCII characters. In case of a system error or when you need to start your system in rescue mode, the keyboard may not be localized.

To change the root password later in the installed system, run YaST and start Security and Users › User and Group Management.

Important
Important: The root user

root is the name of the system administrator or superuser. Its user ID (uid) is 0. Unlike regular users, the root account has unlimited privileges.

Do not forget the root password

Only root has the privileges to change the system configuration, install programs, manage users and set up new hardware. To carry out such tasks, the root password is required. Do not forget the password as it cannot be retrieved later.

Do not use the root user for daily work

Logging in as root for daily work is rather risky: Commands from root are usually executed without additional confirmation, so a single mistake can lead to an irretrievable loss of system files. Only use the root account for system administration, maintenance and repair.

Do not rename the root user account

YaST will always name the system administrator root. While it is technically possible to rename the root account, certain applications, scripts or third-party products may rely on the existence of a user called root. While such a configuration always targets individual environments, necessary adjustments could be overwritten by vendor updates, so this becomes an ongoing task rather than a one-time setting. This is especially true in very complex setups involving third-party applications, where it needs to be verified with every vendor involved whether a rename of the root account is supported.

As the implications for renaming the root account cannot be foreseen, SUSE does not support renaming the root account.

Usually, the idea behind renaming the root account is to hide it or make it unpredictable. However, /etc/passwd requires 644 permissions for regular users, so any user of the system can retrieve the login name for the user ID 0. For better ways to secure the root account, refer to Book “Security and Hardening Guide”, Chapter 14 “User management”, Section 14.5 “Restricting root logins” and Book “Security and Hardening Guide”, Chapter 14 “User management”, Section 14.5.3 “Restricting SSH logins”.

If you want to access the system remotely via SSH using a public key, import a key from a removable storage device or an existing partition. After the installation is finished, you can log in through SSH using the provided SSH key.

Procedure 3.1: Adding a public SSH key for user root

To import a public SSH key from a medium partition, perform the following steps:

  1. The public SSH key is located in your ~/.ssh directory and has the file extension .pub. Copy it to a removable storage device or an existing partition that is not formatted during installation.

  2. If your key is on a removable storage device, insert it into your computer and click Refresh. You should see the device in the drop-down box under Import Public Key.

  3. Click Browse, select the public SSH key and confirm with Open.

  4. Proceed with Next.

If you have both set a password and added a public SSH key, and need remote access right after the installation, do not forget to open the SSH port in the Security section of the Installation Settings summary. If you set no password but only add a key, the port will be opened automatically to prevent you from being locked out of the newly installed system.

3.11 Installation settings Edit source

On the last step before the real installation takes place, you can alter installation settings suggested by the installer. To modify the suggestions, click the respective headline. After having made changes to a particular setting, you are always returned to the Installation Settings window, which is updated accordingly.

If you have added an SSH key for your root as mentioned in Procedure 3.1, make sure to open the SSH port in the Security settings.

Installation Settings
Figure 3.8: Installation settings

3.11.1 Software Edit source

openSUSE Leap contains several software patterns for various application purposes. The available choice of patterns and packages depends on your selection of modules and extensions.

Click Software to open the Software Selection and System Tasks screen where you can modify the pattern selection according to your needs. Select a pattern from the list and see a description in the right-hand part of the window.

Each pattern contains several software packages needed for specific functions (for example Multimedia or Office software). If you chose Generic Desktop in the System Role dialog choose a desktop environment from the list of available Graphical Environments. For a more detailed selection based on software packages to install, select Details to switch to the YaST Software Manager.

Software Selection and System Tasks
Figure 3.9: Software selection and system tasks

You can also install additional software packages or remove software packages from your system at any later time with the YaST Software Manager. For more information, refer to Chapter 9, Installing or removing software.

By default, openSUSE Leap uses the Wayland display server protocol.

Tip
Tip: Adding secondary languages

The language you selected with the first step of the installation will be used as the primary (default) language for the system. You can add secondary languages from within the Software dialog by choosing Details › View › Languages.

3.11.2 Booting Edit source

The installer proposes a boot configuration for your system. Other operating systems found on your computer, such as Microsoft Windows or other Linux installations, will automatically be detected and added to the boot loader. However, openSUSE Leap will be booted by default. Normally, you can leave these settings unchanged. If you need a custom setup, modify the proposal according to your needs. For information, see Book “Reference”, Chapter 12 “The boot loader GRUB 2”, Section 12.3 “Configuring the boot loader with YaST”.

Important
Important: Software RAID 1

Booting a configuration where /boot resides on a software RAID 1 device is supported, but it requires to install the boot loader into the MBR (Boot Loader Location › Boot from Master Boot Record). Having /boot on software RAID devices with a level other than RAID 1 is not supported.

3.11.3 Security Edit source

The CPU Mitigations refer to kernel boot command line parameters for software mitigations that have been deployed to prevent CPU side-channel attacks. Click the selected entry to choose a different option. For details, see Book “Reference”, Chapter 12 “The boot loader GRUB 2” CPU Mitigations.

By default, the Firewall is enabled on all configured network interfaces. To completely disable firewalld, click disable (not recommended).

Note
Note: Firewall settings

When the firewall is activated, all interfaces are assigned to the public zone, where all ports are closed by default, ensuring maximum security. The only port you can open during the installation is port 22 (SSH), to allow remote access. Other services requiring network access (such as FTP, Samba, Web server, etc.) will only work after having adjusted the firewall settings. Refer to Book “Security and Hardening Guide”, Chapter 23 “Masquerading and firewalls” for configuration details.

The SSH service is enabled by default, but its port (22) is closed in the firewall. Click open to open the port or disable to disable the service. Note that if SSH is disabled, remote logins will not be possible. Refer to Book “Security and Hardening Guide”, Chapter 22 “Securing network operations with OpenSSH” for more information.

Tip
Tip: Existing SSH host keys

If you install openSUSE Leap on a machine with existing Linux installations, the installation routine imports an SSH host key. It chooses the host key with the most recent access time by default.

If you are performing a remote administration over VNC, you can also specify whether the machine should be accessible via VNC after the installation. Note that enabling VNC also requires you to set the Default systemd Target to graphical.

The default Major Linux Security Module is AppAmpor. To disable it, select None as module in the Security settings. This allows you to deselect the AppAmor pattern in the Software settings (Section 3.11.1, “Software).

3.11.4 Network configuration Edit source

This category displays the current network settings, as automatically configured after booting into the installation (see Section 3.4) or as manually configured during the installation process. By default, wicked is used for server installations and NetworkManager for desktop workloads.

If you want to check or adjust the network settings, click Network Configuration. This takes you to the YaST Network Settings module. For details, see Book “Reference”, Chapter 13 “Basic networking”, Section 13.4 “Configuring a network connection with YaST”.

3.11.5 Default systemd target Edit source

openSUSE Leap can boot into two different targets (formerly known as runlevels). The graphical target starts a display manager, whereas the multi-user target starts the command line interface.

The default target is graphical. In case you have not installed the X Window System patterns, you need to change it to multi-user. If the system should be accessible via VNC, you need to choose graphical.

3.11.6 Import SSH host keys and configuration Edit source

If an existing Linux installation on your computer was detected, YaST will import the most recent SSH host key found in /etc/ssh by default, optionally including other files in the directory as well. This makes it possible to reuse the SSH identity of the existing installation, avoiding the REMOTE HOST IDENTIFICATION HAS CHANGED warning on the first connection. Note that this item is not shown in the installation summary if YaST has not discovered any other installations. You have the following choices:

I would like to import SSH keys from a previous install:

Select this option to import the SSH host key and optionally the configuration of an installed system. You can select the installation to import from in the option list below.

Import SSH Configuration

Enable this to copy other files in /etc/ssh to the installed system in addition to the host keys.

3.11.7 System Edit source

This screen lists all the hardware information the installer could obtain about your computer. When opened for the first time, the hardware detection is started. Depending on your system, this may take some time. Select any item in the list and click Details to see detailed information about the selected item. Use Save to File to save a detailed list to either the local file system or a removable device.

Advanced users can also change the PCI ID Setup and kernel settings by choosing Kernel Settings. A screen with two tabs opens:

PCI ID setup

Each kernel driver contains a list of device IDs of all devices it supports. If a new device is not in any driver's database, the device is treated as unsupported, even if it can be used with an existing driver. You can add PCI IDs to a device driver here. Only advanced users should attempt to do so.

To add an ID, click Add and select whether to Manually enter the data, or whether to choose from a list. Enter the required data. The SysFS Dir is the directory name from /sys/bus/pci/drivers—if empty, the driver name is used as the directory name. Existing entries can be managed with Edit and Delete.

Kernel settings

Change the Global I/O Scheduler here. If Not Configured is chosen, the default setting for the respective architecture will be used. This setting can also be changed at any time later from the installed system. Refer to Book “System Analysis and Tuning Guide”, Chapter 13 “Tuning I/O performance” for details on I/O tuning.

Also activate the Enable SysRq Keys here. These keys will let you issue basic commands (such as rebooting the system or writing kernel dumps) in case the system crashes. Enabling these keys is recommended when doing kernel development. Refer to https://www.kernel.org/doc/html/latest/admin-guide/sysrq.html for details.

3.12 Performing the installation Edit source

After configuring all installation settings, click Install in the Installation Settings window to start the installation. Some software may require a license confirmation. If your software selection includes such software, license confirmation dialogs are displayed. Click Accept to install the software package. When not agreeing to the license, click I Disagree and the software package will not be installed. In the dialog that follows, confirm with Install again.

The installation usually takes between 15 and 30 minutes, depending on the system performance and the selected software scope. After having prepared the hard disk and having saved and restored the user settings, the software installation starts. Choose Details to switch to the installation log or Release Notes to read important up-to-date information that was not available when the manuals were printed.

After the software installation has completed, the system reboots into the new installation where you can log in. To customize the system configuration or to install additional software packages, start YaST.

4 Troubleshooting Edit source

Abstract

This section covers several common installation problems and describes possible solutions.

4.1 Checking media Edit source

If you encounter any problems using the openSUSE Leap installation media, check its integrity. Boot from the media and choose More › Check Installation Media from the boot menu. A minimal system boots and lets you choose which device to check. Select the respective device and confirm with OK to perform the check.

On a running system, start YaST and choose Software › Media Check. Insert the medium and click Start Check. The integrity check may take time.

If errors are detected during the check, do not use this medium for installation. Media problems may, for example, occur when having burned the medium on DVD yourself. Burning the media at a low speed (4x) helps to avoid problems.

4.2 No bootable drive available Edit source

If your computer cannot boot from USB or DVD drive, you have several alternatives.

Using an external USB flash drive or DVD drive

Linux supports most existing USB flash drives and DVD drives. If the system has no USB flash drive or DVD drive, it is still possible that an external drive, connected through USB, FireWire, or SCSI, can be used to boot the system. Sometimes a firmware update may help if you encounter problems.

Network boot via PXE

If the machine lacks both a USB flash drive and DVD drive, but it has a working Ethernet connection, you can perform a network-based installation.

USB flash drive

You can use a USB flash drive if the machine lacks a DVD drive and a network connection.

4.3 Booting from installation media fails Edit source

The machine may fail to boot from the installation media due to an incorrect boot sequence setting in BIOS. The USB flash drive or DVD drive must be set as the first boot device in the BIOS boot sequence.

Procedure 4.1: Changing the BIOS boot sequence
  1. Enter the BIOS using the proper key shown by the boot routines and wait for the BIOS screen to appear.

  2. To change the boot sequence in an AWARD BIOS, look for the BIOS FEATURES SETUP entry. Other manufacturers may have a different name for this, such as ADVANCED CMOS SETUP. When you have found the entry, select it and confirm with Enter.

  3. Look for a subentry called BOOT SEQUENCE or BOOT ORDER. Change the settings by pressing Page ↑ or Page ↓ until the USB flash drive or DVD drive is listed first.

  4. Exit the BIOS setup screen by pressing Esc. To save the changes, select SAVE & EXIT SETUP, or press F10. To save the modified settings, press Y.

Procedure 4.2: Changing the boot sequence in an SCSI BIOS (Adaptec host adapter)
  1. Open the setup by pressing CtrlA.

  2. Select Disk Utilities. The connected hardware components are now displayed.

    Make note of the SCSI ID of your USB flash drive or DVD drive.

  3. Exit the menu with Esc.

  4. Open Configure Adapter Settings. Under Additional Options, select Boot Device Options and press Enter.

  5. Enter the ID of the USB flash drive or DVD drive and press Enter again.

  6. Press Esc twice to return to the start screen of the SCSI BIOS.

  7. Exit this screen and confirm with Yes to boot the computer.

Regardless of what language and keyboard layout the installed system will be using, most BIOS configurations use the US keyboard layout as shown below.

US keyboard layout
Figure 4.1: US keyboard layout

4.4 Boot failure Edit source

Some hardware types, mainly very old or very recent ones, fail to boot. Reasons can be missing support for hardware in the installation kernel or drivers causing problems on some specific hardware.

If installation fails using the standard Installation mode, try the following.

  1. With the installation media still in the drive, reboot the machine with CtrlAltDel or using the hardware reset button.

  2. When the boot screen appears, press F5, use the arrow keyboard keys to navigate to No ACPI, and press Enter to boot and initiate the installation process. This option disables the support for ACPI power management techniques.

  3. Proceed with the installation as described in Chapter 3, Installation steps.

If this fails, proceed as above, but choose Safe Settings instead. This option disables ACPI and DMA support. This option works with most hardware.

If both options fail, use the boot parameters prompt to specify the kernel parameters to enable support for the hardware in use. For more information about the parameters available as boot parameters, refer to the kernel documentation located in /usr/src/linux/Documentation/kernel-parameters.txt.

Tip
Tip: Obtaining kernel documentation

Install the kernel-source package to view the kernel documentation.

There are other ACPI-related kernel parameters that can be entered at the boot prompt prior to booting for installation:

acpi=off

This parameter disables the complete ACPI subsystem on your computer. This may be useful if your computer cannot handle ACPI or if you think ACPI in your computer causes trouble.

acpi=force

Always enable ACPI even if your computer has a BIOS released before 2000. This parameter also enables ACPI if it is set in addition to acpi=off.

acpi=noirq

Do not use ACPI for IRQ routing.

acpi=ht

Run only enough ACPI to enable hyper-threading.

acpi=strict

Be less tolerant of platforms that are not strictly ACPI-compliant.

pci=noacpi

Disable PCI IRQ routing of the new ACPI system.

pnpacpi=off

Enable this option to avoid issues caused by incorrectly configured device resources in BIOS.

notsc

Disable the time stamp counter. This option can be used to work around timing problems on your systems. It is a recent feature, so if you see regressions on your machine, especially time related or even total hangs, this option is worth a try.

nohz=off

Disable the nohz feature. If your machine hangs, enabling this option may help.

When you have determined the right parameter combination, YaST automatically writes them to the boot loader configuration to make sure that the system boots properly next time.

If errors occur when the kernel is loaded or during the installation, select Memory Test in the boot menu to check the memory. If Memory Test returns an error, this usually indicates a hardware error.

4.5 Graphical installer fails to start Edit source

The machine boots into the installation interface, and the graphical installer does not start when you select Installation.

There are several ways to deal with this situation.

  • Select another screen resolution for the installation dialogs.

  • Select Text Mode for installation.

  • Perform a remote installation via VNC using the graphical installer.

Procedure 4.3: Change screen resolution for installation
  1. Boot for installation.

  2. Press F3 to open a menu from which to select a lower resolution for installation purposes.

  3. Select Installation and proceed with the installation as described in Chapter 3, Installation steps.

Procedure 4.4: Installation in text mode
  1. Boot for installation.

  2. Press F3 and select Text Mode.

  3. Select Installation and proceed with the installation as described in Chapter 3, Installation steps.

Procedure 4.5: VNC installation
  1. Boot for installation.

  2. Enter the following text at the boot parameters prompt:

    vnc=1 vncpassword=SOME_PASSWORD

    Replace SOME_PASSWORD with the password to use for VNC installation.

  3. Select Installation then press Enter to start the installation.

    Instead of starting right into the graphical installation routine, the system continues to run in a text mode. The system then halts, displaying a message containing the IP address and port number at which the installer can be reached via a browser interface or a VNC viewer application.

  4. When using a browser to access the installer, launch the browser and enter the address information provided by the installation routines on the future openSUSE Leap machine and press Enter:

    http://IP_ADDRESS_OF_MACHINE:5801

    A dialog opens in the browser window prompting you for the VNC password. Enter it and proceed with the installation as described in Chapter 3, Installation steps.

    Important
    Important: Cross-platform support

    Installation via VNC works with any browser under any operating system, provided Java support is enabled.

    Provide the IP address and password to your VNC viewer when prompted. A window opens, displaying the installation dialogs. Proceed with the installation as usual.

4.6 Only minimal boot screen is displayed Edit source

You inserted the medium into the drive, the BIOS routines are finished, and the system launches a minimal, text-based interface. This may happen on any machine that does not have sufficient graphics memory for rendering a graphical boot screen.

Although the text boot screen looks minimal, it provides nearly the same functionality as the graphical one.

Boot options

Unlike the graphical interface, the different boot parameters cannot be selected using the cursor keys of your keyboard. The boot menu of the text-mode boot screen provides keywords that can be entered at the boot prompt. These keywords match the options in the graphical version. Enter your choice and press Enter to launch the boot process.

Custom boot options

After selecting a boot parameter, enter the appropriate keyword at the boot prompt or enter some custom boot parameters as described in Section 4.4, “Boot failure”. To launch the installation process, press Enter.

Screen resolutions

Use the function keys (F1 ... F12) to determine the screen resolution for installation. If you need to boot in text mode, choose F3.

Part II Administration Edit source

5 Managing users with YaST

During installation, you may have created a local user for your system. With the YaST module User and Group Management you can add users or edit existing ones. It also lets you configure your system to authenticate users with a network server.

6 Changing language and country settings with YaST

This chapter explains how to configure language and country settings. You can change the language globally for the whole system, individually for certain users or desktops, or temporarily for single applications. Additionally, you can configure secondary languages and adjust the date and country settings.

7 Printer operation

openSUSE® Leap supports printing with many types of printers, including remote network printers. Printers can be configured manually or with YaST. For configuration instructions, refer to Chapter 17, Setting up a printer. Both graphical and command line utilities are available for starting and manag…

8 Accessing file systems with FUSE

FUSE is the acronym for file system in user space. This means you can configure and mount a file system as an unprivileged user. Normally, you need to be root for this task. FUSE alone is a kernel module. Combined with plug-ins, it allows you to extend FUSE to access almost all file systems like remote SSH connections, ISO images, and more.

5 Managing users with YaST Edit source

During installation, you may have created a local user for your system. With the YaST module User and Group Management you can add users or edit existing ones. It also lets you configure your system to authenticate users with a network server.

5.1 User and group administration dialog Edit source

To administer users or groups, start YaST and click Security and Users › User and Group Management. Alternatively, start the User and Group Administration dialog directly by running sudo yast2 users & from a command line.

YaST user and group administration
Figure 5.1: YaST user and group administration

Every user is assigned a system-wide user ID (UID). Apart from the users that can log in to your machine, there are also several system users for internal use only. Each user is assigned to one or more groups. Similar to system users, there are also system groups for internal use.

The main window shows several tabs, depending on the set of users (local users, network users, system users) you choose to view and modify. The tabs allow you to perform the following tasks:

Managing user accounts

From the Users tab create, modify, delete or temporarily disable user accounts as described in Section 5.2, “Managing user accounts”. Learn about advanced options like enforcing password policies, using encrypted home directories, or managing disk quotas in Section 5.3, “Additional options for user accounts”.

Changing default settings

Local user accounts are created according to the settings defined on the Defaults for New Users tab. Learn how to change the default group assignment, or the default path and access permissions for home directories in Section 5.4, “Changing default settings for local users”.

Assigning users to groups

Learn how to change the group assignment for individual users in Section 5.5, “Assigning users to groups”.

Managing groups

From the Groups tab, you can add, modify or delete existing groups. Refer to Section 5.6, “Managing groups” for information on how to do this.

Changing user authentication method

When your machine is connected to a network that provides user authentication methods like NIS or LDAP, you can choose between several authentication methods on the Authentication Settings tab. For more information, refer to Section 5.7, “Changing the user authentication method”.

For user and group management, the dialog provides similar functionality. You can easily switch between the user and group administration view by choosing the appropriate tab at the top of the dialog.

Filter options allow you to define the set of users or groups you want to modify: on the Users or Group tab, click Set Filter to view and edit users or groups. They are listed according to certain categories, such as Local Users or LDAP Users, if applicable. With Set Filter › Customize Filter you can also set up and use a custom filter.

Depending on the filter you choose, not all the following options and functions may be available from the dialog.

5.2 Managing user accounts Edit source

YaST allows you to create, modify, delete or temporarily disable user accounts. Do not modify user accounts unless you are an experienced user or administrator.

Note
Note: Changing user IDs of existing users

File ownership is bound to the user ID, not to the user name. After a user ID change, the files in the user's home directory are automatically adjusted to reflect this change. However, after an ID change, the user no longer owns the files they created elsewhere in the file system unless the file ownership for those files are manually modified.

The following instructions demonstrate how to set up default user accounts. For further options, refer to Section 5.3, “Additional options for user accounts”.

Procedure 5.1: Adding or modifying user accounts
  1. Open the YaST User and Group Administration dialog and click the Users tab.

  2. With Set Filter define the set of users you want to manage. The dialog lists users in the system and the groups the users belong to.

  3. To modify options for an existing user, select an entry and click Edit.

    To create a new user account, click Add.

  4. Enter the appropriate user data on the first tab, such as Username (which is used for login) and Password. This data is sufficient to create a new user. If you click OK now, the system automatically assigns a user ID and sets all other values as default.

  5. Activate Receive System Mail if you want system notifications to be delivered to this user's mailbox. This creates a mail alias for root and the user can read the system mail without having to first log in as root.

    The mails sent by system services are stored in the local mailbox /var/spool/mail/USERNAME, where USERNAME is the login name of the selected user. To read e-mails, you can use the mail command.

  6. To adjust further details such as the user ID or the path to the user's home directory, do so on the Details tab.

    If you need to relocate the home directory of an existing user, enter the path to the new home directory there and move the contents of the current home directory with Move to New Location. Otherwise, a new home directory is created without any of the existing data.

  7. To force users to regularly change their password or set other password options, switch to Password Settings and adjust the options. For more details, refer to Section 5.3.2, “Enforcing password policies”.

  8. If all options are set according to your wishes, click OK.

  9. Click OK to close the administration dialog and to save the changes. A newly added user can now log in to the system using the login name and password you created.

    Alternatively, to save all changes without exiting the User and Group Administration dialog, click Expert Options › Write Changes Now.

Warning
Warning: Do not rename the root account

While it is technically possible to rename the root account, certain applications, scripts or third-party products may rely on the existence of a user called root. While such a configuration always targets individual environments, necessary adjustments could be overwritten by vendor updates, so this becomes an ongoing task rather than a one-time setting. This is especially true in complex setups involving third-party applications, where it needs to be verified with every vendor involved whether a rename of the root account is supported.

As the implications for renaming the root account cannot be foreseen, SUSE does not support renaming the root account.

Usually, the idea behind renaming the root account is to hide it or make it unpredictable. However, /etc/passwd requires 644 permissions for regular users, so any user of the system can retrieve the login name for the user ID 0. For better ways to secure the root account, refer to Book “Security and Hardening Guide”, Chapter 14 “User management”, Section 14.5 “Restricting root logins” and Book “Security and Hardening Guide”, Chapter 14 “User management”, Section 14.5.3 “Restricting SSH logins”.

Tip
Tip: Matching user IDs

It is useful to match the (local) user ID to the ID in the network. For example, a new (local) user on a laptop should be integrated into a network environment with the same user ID. This ensures that the file ownership of the files the user creates offline is the same as if they had created them directly on the network.

Procedure 5.2: Disabling or deleting user accounts
  1. Open the YaST User and Group Administration dialog and click the Users tab.

  2. To temporarily disable a user account without deleting it, select the user from the list and click Edit. Activate Disable User Login. The user cannot log in to your machine until you enable the account again.

  3. To delete a user account, select the user from the list and click Delete. Choose if you also want to delete the user's home directory or to retain the data.

5.3 Additional options for user accounts Edit source

Besides the settings for a default user account, openSUSE® Leap offers further options. For example, options to enforce password policies, use encrypted home directories or define disk quotas for users and groups.

5.3.1 Automatic login and passwordless login Edit source

If you use the GNOME desktop environment you can configure Auto Login for a certain user and Passwordless Login for all users. Auto login causes a user to become automatically logged in to the desktop environment on boot. This functionality can only be activated for one user at a time. Login without password allows all users to log in to the system after they have entered their user name in the login manager.

Warning
Warning: Security risk

Enabling Auto Login or Passwordless Login on a machine that can be accessed by more than one person is a security risk. Without the need to authenticate, any user can gain access to your system and your data. If your system contains confidential data, do not use this functionality.

To activate auto login or login without password, access these functions in the YaST User and Group Administration with Expert Options › Login Settings.

5.3.2 Enforcing password policies Edit source

On any system with multiple users, it is a good idea to enforce at least basic password security policies. Users should change their passwords regularly and use strong passwords that cannot easily be exploited. For local users, proceed as follows:

Procedure 5.3: Configuring password settings
  1. Open the YaST User and Group Administration dialog and select the Users tab.

  2. Select user and click Edit.

  3. Switch to the Password Settings tab. The user's last password change is displayed on the tab.

  4. To make the user change their password at next login, activate Force Password Change.

  5. To enforce password rotation, set a Maximum Number of Days for the Same Password and a Minimum Number of Days for the Same Password.

  6. To remind the user to change their password before it expires, set the number of Days before Password Expiration to Issue Warning.

  7. To restrict the period of time the user can log in after their password has expired, change the value in Days after Password Expires with Usable Login.

  8. You can also specify a certain expiration date for the complete account. Enter the Expiration Date in YYYY-MM-DD format. This setting is not password-related but rather applies to the account itself.

  9. For more information about options and default values, click Help.

  10. Apply your changes with OK.

5.3.3 Managing quotas Edit source

To prevent system capacities from being exhausted without notification, system administrators can set up quotas for users or groups. Quotas can be defined for one or more file systems and restrict the amount of disk space that can be used and the number of inodes (index nodes) that can be created there. Inodes are data structures on a file system that store basic information about a regular file, directory or other file system object. They store all attributes of a file system object (like user and group ownership, read, write or execute permissions), except file name and contents.

openSUSE Leap allows usage of soft and hard quotas. Additionally, grace intervals can be defined that allow users or groups to temporarily exceed their quotas by certain amounts.

Soft quota

Defines a warning level at which users are informed that they are nearing their limit. Administrators may urge the users to clean up and reduce their data on the partition. The soft quota limit is normally lower than the hard quota limit.

Hard quota

Defines the limit at which write requests are denied. When the hard quota is reached, no more data can be stored and applications may crash.

Grace period

Defines the time between the overflow of the soft quota and a warning being issued. Normally set to a rather low value of one or several hours.

Procedure 5.4: Enabling quota support for a partition

To configure quotas for certain users and groups, you need to enable quota support for the respective partition in the YaST Expert Partitioner first.

  1. In YaST, select System › Partitioner and click Yes to proceed.

  2. In the Expert Partitioner, select the partition for which to enable quotas and click Edit.

  3. Click Fstab Options and activate Enable Quota Support. If the quota package is not already installed, it will be installed when you confirm the respective message with Yes.

  4. Confirm your changes and leave the Expert Partitioner.

  5. Make sure the service quotaon is running by entering the following command:

    > sudo systemctl status quotaon.service

    It should be marked as being active. If this is not the case, start it with the command systemctl start quotaon.service.

Procedure 5.5: Setting up quotas for users or groups

Now you can define soft or hard quotas for specific users or groups and set time periods as grace intervals.

  1. In the YaST User and Group Administration, select the user or the group you want to set the quotas for and click Edit.

  2. On the Plug-Ins tab, select the Manage User Quota entry and click Launch to open the Quota Configuration dialog.

  3. From File System, select the partition to which the quota should apply.

  4. Below Size Limits, restrict the amount of disk space. Enter the number of 1 KB blocks the user or group may have on this partition. Specify a Soft Limit and a Hard Limit value.

  5. Additionally, you can restrict the number of inodes the user or group may have on the partition. Below Inodes Limits, enter a Soft Limit and Hard Limit.

  6. You can only define grace intervals if the user or group has already exceeded the soft limit specified for size or inodes. Otherwise, the time-related text boxes are not activated. Specify the time period for which the user or group is allowed to exceed the limits set above.

  7. Confirm your settings with OK.

  8. Click OK to close the administration dialog and save the changes.

    Alternatively, to save all changes without exiting the User and Group Administration dialog, click Expert Options › Write Changes Now.

openSUSE Leap also ships command line tools like repquota or warnquota. System administrators can use these tools to control the disk usage or send e-mail notifications to users exceeding their quota. Using quota_nld, administrators can also forward kernel messages about exceeded quotas to D-BUS. For more information, refer to the repquota, the warnquota and the quota_nld man page.

5.4 Changing default settings for local users Edit source

When creating new local users, several default settings are used by YaST. These include, for example, the group the user belongs to, or the access permissions of the user's home directory. You can change these default settings to meet your requirements:

  1. Open the YaST User and Group Administration dialog and select the Defaults for New Users tab.

  2. To change the group the new users should automatically belong to, select another group from Default Group.

  3. If you do not want to use /home/USERNAME as the default path for new users' home directories, modify the Path Prefix for Home Directory.

  4. To change the default permission modes for newly created home directories, adjust the umask value in Umask for Home Directory. For more information about umask, refer to Book “Security and Hardening Guide”, Chapter 19 “Access control lists in Linux” and to the umask man page.

  5. For information about the individual options, click Help.

  6. Apply your changes with OK.

5.5 Assigning users to groups Edit source

Local users are assigned to several groups according to the default settings, which you can access from the User and Group Administration dialog on the Defaults for New Users tab. In the following, learn how to modify an individual user's group assignment. If you need to change the default group assignments for new users, refer to Section 5.4, “Changing default settings for local users”.

Procedure 5.6: Changing a user's group assignment
  1. Open the YaST User and Group Administration dialog and click the Users tab. It lists users and the groups the users belong to.

  2. Click Edit and switch to the Details tab.

  3. To change the group the user belongs to, click Default Group and select the group from the list.

  4. To assign the user additional secondary groups, activate the corresponding check boxes in the Additional Groups list.

  5. Click OK to apply your changes.

  6. Click OK to close the administration dialog and save the changes.

    Alternatively, to save all changes without exiting the User and Group Administration dialog, click Expert Options › Write Changes Now.

5.6 Managing groups Edit source

With YaST you can also easily add, modify or delete groups.

Procedure 5.7: Creating and modifying groups
  1. Open the YaST User and Group Management dialog and click the Groups tab.

  2. With Set Filter define the set of groups you want to manage. The dialog lists groups in the system.

  3. To create a new group, click Add.

  4. To modify an existing group, select the group and click Edit.

  5. In the following dialog, enter or change the data. The list on the right shows an overview of all available users and system users which can be members of the group.

  6. To add existing users to a new group select them from the list of possible Group Members by checking the corresponding box. To remove them from the group deactivate the box.

  7. Click OK to apply your changes.

  8. Click OK to close the administration dialog and save the changes.

    Alternatively, to save all changes without exiting the User and Group Administration dialog, click Expert Options › Write Changes Now.

To delete a group, it must not contain any group members. To delete a group, select it from the list and click Delete. Click OK to close the administration dialog and save the changes. Alternatively, to save all changes without exiting the User and Group Administration dialog, click Expert Options › Write Changes Now.

5.7 Changing the user authentication method Edit source

When your machine is connected to a network, you can change the authentication method. The following options are available:

NIS

Users are administered centrally on a NIS server for all systems in the network. For details, see Book “Security and Hardening Guide”, Chapter 3 “Using NIS”.

SSSD

The System Security Services Daemon (SSSD) can locally cache user data and then allow users to use the data, even if the real directory service is (temporarily) unreachable. For details, see Book “Security and Hardening Guide”, Chapter 4 “Setting up authentication clients using YaST”, Section 4.2 “SSSD”.

Samba

SMB authentication is often used in mixed Linux and Windows networks. For details, see Book “Security and Hardening Guide”, Chapter 7 “Active Directory support”.

To change the authentication method, proceed as follows:

  1. Open the User and Group Administration dialog in YaST.

  2. Click the Authentication Settings tab to show an overview of the available authentication methods and the current settings.

  3. To change the authentication method, click Configure and select the authentication method you want to modify. This takes you directly to the client configuration modules in YaST. For information about the configuration of the appropriate client, refer to the following sections:

    NIS:  Book “Security and Hardening Guide”, Chapter 3 “Using NIS”, Section 3.2 “Configuring NIS clients”

    LDAP:  Book “Security and Hardening Guide”, Chapter 4 “Setting up authentication clients using YaST”, Section 4.1 “Configuring an authentication client with YaST”

    SSSD:  Book “Security and Hardening Guide”, Chapter 4 “Setting up authentication clients using YaST”, Section 4.2 “SSSD”

  4. After accepting the configuration, return to the User and Group Administration overview.

  5. Click OK to close the administration dialog.

5.8 Default system users Edit source

By default, openSUSE Leap creates user names, which cannot be deleted. These users are typically defined in the Linux Standard Base. The following list provides the common user names and their purpose:

Common user names installed by default
bin, daemon

Legacy user, included for compatibility with legacy applications. New applications should no longer use this user name.

gdm

Used by GNOME Display Manager (GDM) to provide graphical logins and manage local and remote displays.

lp

Used by the Printer daemon for Common Unix Printing System (CUPS).

mail

User reserved for mailer programs like sendmail or postfix.

man

Used by man to access man pages.

messagebus

Used to access D-Bus (desktop bus), a software bus for inter-process communication. Daemon is dbus-daemon.

nobody

User that owns no files and is in no privileged groups. Nowadays, its use is limited as it is recommended by Linux Standard Base to provide a separate user account for each daemon.

nscd

Used by the Name Service Caching Daemon. This daemon is a lookup service to improve performance with NIS and LDAP. Daemon is nscd.

polkitd

Used by the PolicyKit Authorization Framework, which defines and handles authorization requests for unprivileged processes. Daemon is polkitd.

postfix

Used by the Postfix mailer.

pulse

Used by the Pulseaudio sound server.

root

Used by the system administrator, providing all appropriate privileges.

rpc

Used by the rpcbind command, an RPC port mapper.

rtkit

Used by the rtkit package providing a D-Bus system service for real time scheduling mode.

salt

User for parallel remote execution provided by Salt. Daemon is named salt-master.

scard

User for communication with smart cards and readers. Daemon is named pcscd.

srvGeoClue

Used by the GeoClue D-Bus service to provide location information.

sshd

Used by the Secure Shell daemon (SSH) to ensure secured and encrypted communication over an insecure network.

statd

Used by the Network Status Monitor protocol (NSM), implemented in the rpc.statd daemon, to listen for reboot notifications.

systemd-coredump

Used by the /usr/lib/systemd/systemd-coredump command to acquire, save and process core dumps.

systemd-network

Used by the /usr/lib/systemd/systemd-networkd command to manage networks.

systemd-timesync

Used by the /usr/lib/systemd/systemd-timesyncd command to synchronize the local system clock with a remote Network Time Protocol (NTP) server.

5.9 Default system groups Edit source

By default, SLE creates multiple user groups that are used by system services. The following list describes examples of required and common optional groups.

root

Administrative group with all privileges.

bin

Included for compatibility with legacy applications. New applications should not use this group.

daemon

Previously used to limit daemons' access to the system. Daemons should run under their own UID/GID now to separate daemons from one another.

audio

Privileges for audio devices.

gdm

Privileges for the GNOME Display Manager.

chrony

Privileges for the time synchronization service.

kvm

Privileges for the QEMU machine emulator toolkit.

libvirt

Privileges for virtualization stack.

lp

Privileges for printer operation.

mail

Privileges for mail services.

man

Privileges specific to manual pages and the man command.

sshd

Privileges for SSH communication protocol daemon.

6 Changing language and country settings with YaST Edit source

Abstract

This chapter explains how to configure language and country settings. You can change the language globally for the whole system, individually for certain users or desktops, or temporarily for single applications. Additionally, you can configure secondary languages and adjust the date and country settings.

If you work in different countries or in a multilingual environment, you should configure your system accordingly. openSUSE® Leap can handle different locales in parallel. A locale is a set of parameters that defines the language and country settings reflected in the user interface.

The main system language is selected during installation, and keyboard and time zone settings are adjusted accordingly. However, you can install additional languages and determine which of the installed languages should be the default.

For those tasks, use the YaST language module as described in Section 6.1, “Changing the system language”. Install secondary languages to get optional localization if you need to start applications or desktops in languages other than the primary one.

The YaST time zone module allows you to adjust your country and time zone settings accordingly. It also lets you synchronize your system clock against a time server. For details, refer to Section 6.2, “Changing the country and time settings”.

6.1 Changing the system language Edit source

Depending on how you use your desktop and whether you want to switch the entire system to another language or only the desktop environment, you have several options:

Changing the system language globally

Proceed as described in Section 6.1.1, “Modifying system languages with YaST” and Section 6.1.2, “Switching the default system language” to install additional localized packages with YaST and to set the default language. Changes are effective after the next login. To ensure that the entire system reflects the change, reboot the system or close and restart all running services, applications and programs.

Changing the language for the desktop only

Provided you have previously installed the desired language packages for your desktop environment with YaST as described below, you can switch the language of your desktop using the desktop's control center. Refer to Book “GNOME User Guide”, Chapter 3 “Customizing your settings”, Section 3.2 “Configuring language settings” for details. After the X server has been restarted, your entire desktop reflects your new choice of language. Applications not belonging to your desktop framework are not affected by this change and may still appear in the language that was set in YaST.

Temporarily switching languages for one application only

You can also run a single application in another language (that has already been installed with YaST). To do so, start it from the command line by specifying the language code as described in Section 6.1.3, “Switching languages for standard X and GNOME applications”.

6.1.1 Modifying system languages with YaST Edit source

YaST supports two different language categories:

Primary Language

The primary language set in YaST applies to the entire system, including YaST and the desktop environment. This language is used whenever available unless you manually specify another language.

Secondary Languages

Install secondary languages to make your system multilingual. Languages installed as secondary can be selected manually, when needed. For example, use a secondary language to start an application in a certain language to do word processing in this language.

Before installing additional languages, determine which of them should be the default system language (primary language).

To access the YaST language module, start YaST and click System › Language. Alternatively, start the Languages dialog directly by running sudo yast2 language & from a command line.

Procedure 6.1: Installing additional languages

When installing additional languages, YaST allows you to set different locale settings for the user root, see Step 4. The option Locale Settings for User root determines how the locale variables (LC_*) in the file /etc/sysconfig/language are set for root. You can set them to the same locale as for regular users. Alternatively, you can keep them unaffected by any language changes, or only set the variable RC_LC_CTYPE to the same values as for the regular users. The RC_LC_CTYPE variable sets the localization for language-specific function calls.

  1. To add languages in the YaST language module, select the Secondary Languages you want to install.

  2. To make a language the default language, set it as Primary Language.

  3. Additionally, adapt the keyboard to the new primary language and adjust the time zone, if appropriate.

    Tip
    Tip: Advanced settings

    For advanced keyboard or time zone settings, select Hardware › System Keyboard Layout or System › Date and Time in YaST. For more information, refer to Chapter 15, Setting up your system keyboard layout and Section 6.2, “Changing the country and time settings”.

  4. To change language settings specific to the user root, click Details.

    1. Set Locale Settings for User root to the desired value. For more information, click Help.

    2. Decide whether to use Use UTF-8 Encoding for root or not.

  5. If your locale was not included in the list of primary languages available, try specifying it with Detailed Locale Setting. However, this may result in certain locales being incomplete.

  6. Confirm the changes in the dialogs with OK. If you have selected secondary languages, YaST installs the localized software packages for the additional languages.

The system is now multilingual. However, to start an application in a language other than the primary one, you need to set the desired language explicitly as explained in Section 6.1.3, “Switching languages for standard X and GNOME applications”.

6.1.2 Switching the default system language Edit source

To globally change the default language of a system, use the following procedure:

  1. Start the YaST language module.

  2. Select the desired new system language as Primary Language.

    Important
    Important: Deleting former system languages

    If you switch to a different primary language, the localized software packages for the former primary language gets removed from the system. To switch the default system language but keep the former primary language as an additional language, add it as Secondary Language by selecting the respective check box.

  3. Adjust the keyboard and time zone options as desired.

  4. Confirm your changes with OK.

  5. After YaST has applied the changes, restart current X sessions (for example, by logging out and logging in again) to make YaST and the desktop applications reflect your new language settings.

6.1.3 Switching languages for standard X and GNOME applications Edit source

After you have installed the respective language with YaST, you can run a single application in another language.

Start the application from the command line by using the following command:

LANG=LANGUAGE application

For example, to start f-spot in German, run LANG=de_DE f-spot. For other languages, use the appropriate language code. Get a list of all language codes available with the locale  -av command.

6.2 Changing the country and time settings Edit source

Using the YaST date and time module, adjust your system date, clock and time zone information to the area you are working in. To access the YaST module, start YaST and click System › Date and Time. Alternatively, start the Clock and Time Zone dialog directly by running sudo yast2 timezone & from a command line.

First, select a general region, such as Europe. Choose an appropriate country that matches the one you are working in, for example, Germany.

Depending on which operating systems run on your workstation, adjust the hardware clock settings accordingly:

  • If you run another operating system on your machine, such as Microsoft Windows*, your system may not use UTC, but local time. In this case, deactivate Hardware Clock Set To UTC.

  • If you only run Linux on your machine, set the hardware clock to UTC and have the switch from standard time to daylight saving time performed automatically.

Important
Important: Set the hardware clock to UTC

The switch from standard time to daylight saving time (and vice versa) can only be performed automatically when the hardware clock (CMOS clock) is set to UTC. This also applies if you use automatic time synchronization with NTP, because automatic synchronization is only performed if the time difference between the hardware and system clock is less than 15 minutes.

Since a wrong system time can cause serious problems (missed backups, dropped mail messages, mount failures on remote file systems, etc.) it is strongly recommended to always set the hardware clock to UTC.

You can change the date and time manually or opt for synchronizing your machine against an NTP server, either permanently or only for adjusting your hardware clock.

Procedure 6.2: Manually adjusting time and date
  1. In the YaST timezone module, click Other Settings to set date and time.

  2. Select Manually and enter date and time values.

  3. Confirm your changes.

Procedure 6.3: Setting date and time with NTP server
  1. Click Other Settings to set date and time.

  2. Select Synchronize with NTP Server.

  3. Enter the address of an NTP server, if not already populated.

  4. With the Configure button, you can open the advanced NTP configuration. For details, see Book “Reference”, Chapter 18 “Time synchronization with NTP”, Section 18.1 “Configuring an NTP client with YaST”.

  5. Confirm your changes.

7 Printer operation Edit source

openSUSE® Leap supports printing with many types of printers, including remote network printers. Printers can be configured manually or with YaST. For configuration instructions, refer to Chapter 17, Setting up a printer. Both graphical and command line utilities are available for starting and managing print jobs. If your printer does not work as expected, refer to Section 7.8, “Troubleshooting”.

CUPS (Common Unix Printing System) is the standard print system in openSUSE Leap.

Printers can be distinguished by interface, such as USB or network, and printer language. When buying a printer, make sure that the printer has an interface that is supported (USB, Ethernet or Wi-Fi) and a suitable printer language. Printers can be categorized on the basis of the following three classes of printer languages:

PostScript printers

PostScript is the printer language in which most print jobs in Linux and Unix are generated and processed by the internal print system. If PostScript documents can be processed directly by the printer and do not need to be converted in additional stages in the print system, the number of potential error sources is reduced.

Currently PostScript is being replaced by PDF as the standard print job format. PostScript+PDF printers that can directly print PDF (in addition to PostScript) already exist. For traditional PostScript printers PDF needs to be converted to PostScript in the printing workflow.

Standard printers (languages like PCL and ESC/p)

For known printer languages, the print system can convert PostScript jobs to the respective printer language with Ghostscript. This processing stage is called interpreting. The best-known languages are PCL (which is used by HP printers and their clones) and ESC/P (which is used by Epson printers). These printer languages are normally supported by Linux and produce an adequate print result. Linux may not be able to address certain special printer functions. Except for HP and Epson, there are currently no printer manufacturers who develop Linux drivers and make them available to Linux distributors under an open source license.

Proprietary printers (also called GDI printers)

These printers do not support any of the common printer languages. They use their own undocumented printer languages, which are subject to change when a new edition of a model is released. Normally, only Windows drivers are available for these printers. See Section 7.8.1, “Printers without standard printer language support” for more information.

Before you buy a new printer, refer to the following sources to check how well the printer you intend to buy is supported:

https://www.openprinting.org/printers

The OpenPrinting home page with the printer database. The database shows the latest Linux support status. However, a Linux distribution can only integrate the drivers available at production time. Accordingly, a printer currently rated as perfectly supported may not have had this status when the latest openSUSE Leap version was released. Thus, the databases may not necessarily indicate the correct status, but only provide an approximation.

https://pages.cs.wisc.edu/~ghost/

The Ghostscript Web page.

/usr/share/doc/packages/ghostscript/catalog.devices

List of built-in Ghostscript drivers.

7.1 The CUPS workflow Edit source

The user creates a print job. The print job consists of the data to print plus information for the spooler. This includes the name of the printer or the name of the print queue, and optionally, information for the filter, such as printer-specific options.

At least one dedicated print queue exists for every printer. The spooler holds the print job in the queue until the desired printer is ready to receive data. When the printer is ready, the spooler sends the data through the filter and back-end to the printer.

The filter converts the data generated by the application that is printing (normally PostScript or PDF, but also ASCII, JPEG, etc.) into printer-specific data (PostScript, PCL, ESC/P, etc.). The features of the printer are described in the PPD files. A PPD file contains printer-specific options with the parameters needed to enable them on the printer. The filter system makes sure that options selected by the user are enabled.

If you use a PostScript printer, the filter system converts the data into printer-specific PostScript. This does not require a printer driver. If you use a non-PostScript printer, the filter system converts the data into printer-specific data. This requires a printer driver suitable for your printer. The back-end receives the printer-specific data from the filter then passes it to the printer.

7.2 Methods and protocols for connecting printers Edit source

There are multiple possibilities for connecting a printer to the system. The configuration of CUPS does not distinguish between a local printer and a printer connected to the system over the network. For more information about the printer connection, read the article CUPS in a Nutshell at https://en.opensuse.org/SDB:CUPS_in_a_Nutshell.

Warning
Warning: Changing cable connections in a running system

When connecting the printer to the machine, do not forget that only USB devices can be plugged in or unplugged during operation. To avoid damaging your system or printer, shut down the system before changing any connections that are not USB.

7.3 Installing the software Edit source

PPD (PostScript printer description) is the computer language that describes the properties, like resolution, and options, such as the availability of a duplex unit. These descriptions are required for using printer options in CUPS. Without a PPD file, the print data would be forwarded to the printer in a raw state, which is not desired.

To configure a PostScript printer, the best approach is to get a suitable PPD file. Many PPD files are available in the packages manufacturer-PPDs and OpenPrintingPPDs-postscript. See Section 7.7.3, “PPD files in multiple packages” and Section 7.8.2, “No suitable PPD file available for a PostScript printer”.

New PPD files can be stored in the directory /usr/share/cups/model/ or added to the print system with YaST as described in Section 17.1.1, “Adding drivers with YaST”. Subsequently, the PPD file can be selected during the printer setup.

Be careful if a printer manufacturer wants you to install entire software packages. This kind of installation may result in the loss of the support provided by openSUSE Leap. Also, print commands may work differently and the system may no longer be able to address devices of other manufacturers. For this reason, the installation of manufacturer software is not recommended.

7.4 Network printers Edit source

A network printer can support multiple protocols. Although most of the supported protocols are standardized, certain manufacturers modify the standard. Manufacturers then provide drivers for only a few operating systems and Linux drivers are rarely provided. The current situation is such that you cannot act on the assumption that every protocol works smoothly in Linux. Therefore, you may need to experiment with several options to achieve a functional configuration.

CUPS supports the socket, LPD, IPP and smb protocols.

socket

Socket refers to a connection in which the plain print data is sent directly to a TCP socket. Socket port numbers that are commonly used are 9100 or 35. The device URI (uniform resource identifier) syntax is: socket://IP.OF.THE.PRINTER:PORT, for example: socket://192.168.2.202:9100/.

LPD (line printer daemon)

The LPD protocol is described in RFC 1179. Under this protocol, specific job-related data, such as the ID of the print queue, is sent before the actual print data is sent. Therefore, a print queue must be specified when configuring the LPD protocol. The implementations of diverse printer manufacturers are flexible enough to accept any name as the print queue. If necessary, the printer manual should indicate what name to use. LPT, LPT1, LP1 or similar names are often used. The port number for an LPD service is 515. An example device URI is lpd://192.168.2.202/LPT1.

IPP (Internet printing protocol)

IPP is based on the HTTP protocol. With IPP, more job-related data is transmitted than with the other protocols. CUPS uses IPP for internal data transmission. The name of the print queue is necessary to configure IPP correctly. The port number for IPP is 631. Example device URIs are ipp://192.168.2.202/ps and ipp://192.168.2.202/printers/ps.

SMB (Windows share)

CUPS also supports printing on printers connected to Windows shares. The protocol used for this purpose is SMB. SMB uses the port numbers 137, 138 and 139. Example device URIs are smb://user:password@workgroup/smb.example.com/printer, smb://user:password@smb.example.com/printer, and smb://smb.example.com/printer.

The protocol supported by the printer must be determined before configuration. If the manufacturer does not provide the needed information, the command nmap (which comes with the nmap package) can be used to ascertain the protocol. nmap checks a host for open ports. For example:

> nmap -p 35,137-139,515,631,9100-10000 IP.OF.THE.PRINTER

7.5 Configuring CUPS with command line tools Edit source

CUPS can be configured with command line tools like lpinfo, lpadmin and lpoptions. You need a device URI consisting of a back-end, such as USB, and parameters. To determine valid device URIs on your system use the command lpinfo -v | grep ":/":

> sudo lpinfo -v | grep ":/"
direct usb://ACME/FunPrinter%20XL
network socket://192.168.2.253

With lpadmin the CUPS server administrator can add, remove or manage print queues. To add a print queue, use the following syntax:

> sudo lpadmin -p QUEUE -v DEVICE-URI -P PPD-FILE -E

Then the device (-v) is available as QUEUE (-p), using the specified PPD file (-P). This means that you must know the PPD file and the device URI to configure the printer manually.

Do not use -E as the first option. For all CUPS commands, -E as the first argument sets use of an encrypted connection. To enable the printer, -E must be used as shown in the following example:

> sudo lpadmin -p ps -v usb://ACME/FunPrinter%20XL -P \
/usr/share/cups/model/Postscript.ppd.gz -E

The following example configures a network printer:

> sudo lpadmin -p ps -v socket://192.168.2.202:9100/ -P \
/usr/share/cups/model/Postscript-level1.ppd.gz -E

For more options of lpadmin, see the man page of lpadmin(8).

During printer setup, certain options are set as default. These options can be modified for every print job (depending on the print tool used). Changing these default options with YaST is also possible. Using command line tools, set default options as follows:

  1. First, list all options:

    > sudo lpoptions -p QUEUE -l

    Example:

    Resolution/Output Resolution: 150dpi *300dpi 600dpi

    The activated default option is identified by a preceding asterisk (*).

  2. Change the option with lpadmin:

    > sudo lpadmin -p QUEUE -o Resolution=600dpi
  3. Check the new setting:

    > sudo lpoptions -p QUEUE -l
    
    Resolution/Output Resolution: 150dpi 300dpi *600dpi

When a normal user runs lpoptions, the settings are written to ~/.cups/lpoptions. However, root settings are written to /etc/cups/lpoptions.

7.6 Printing from the command line Edit source

To print from the command line, enter lp -d QUEUENAME FILENAME, substituting the corresponding names for QUEUENAME and FILENAME.

Several applications rely on the lp command for printing. In this case, enter the correct command in the application's print dialog, normally without specifying FILENAME, for example, lp -d QUEUENAME.

7.7 Special features in openSUSE Leap Edit source

Several CUPS features have been adapted for openSUSE Leap. The most important changes are covered here.

7.7.1 CUPS and firewall Edit source

After completing a default installation of openSUSE Leap, firewalld is active and the network interfaces are configured to be in the public zone, which blocks incoming traffic.

When firewalld is active, you may need to configure it to allow clients to browse network printers by allowing mdns and ipp through the internal network zone. The public zone should never expose printer queues.

(More information about the firewalld configuration is available in Book “Security and Hardening Guide”, Chapter 23 “Masquerading and firewalls”, Section 23.4 “firewalld and at https://en.opensuse.org/SDB:CUPS_and_SANE_Firewall_settings.)

7.7.1.1 CUPS client Edit source

Normally, a CUPS client runs on a regular workstation located in a trusted network environment behind a firewall. In this case, it is recommended to configure the network interface to be in the Internal Zone, so the workstation is reachable from within the network.

7.7.1.2 CUPS server Edit source

If the CUPS server is part of a trusted network environment protected by a firewall, the network interface should be configured to be in the Internal Zone of the firewall. It is not recommended to set up a CUPS server in an untrusted network environment unless you ensure that it is protected by special firewall rules and secure settings in the CUPS configuration.

7.7.2 Browsing for network printers Edit source

CUPS servers regularly announce the availability and status information of shared printers over the network. Clients can access this information to display a list of available printers in printing dialogs, for example. This is called browsing.

CUPS servers announce their print queues over the network either via the traditional CUPS browsing protocol, or via Bonjour/DNS-SD. To enable browsing network print queues, the service cups-browsed needs to run on all clients that print via CUPS servers. cups-browsed is not started by default. To start it for the active session, use sudo systemctl start cups-browsed. To ensure it is automatically started after booting, enable it with sudo systemctl enable cups-browsed on all clients.

In case browsing does not work after having started cups-browsed, the CUPS servers announce the network print queues via Bonjour/DNS-SD. In this case, you need to additionally install the package avahi and start the associated service with sudo systemctl start avahi-daemon on all clients.

See Section 7.7.1, “CUPS and firewall” for information on allowing printer browsing through firewalld.

7.7.3 PPD files in multiple packages Edit source

The YaST printer configuration sets up the queues for CUPS using the PPD files installed in /usr/share/cups/model. To find the suitable PPD files for the printer model, YaST compares the vendor and model determined during hardware detection with the vendors and models in all PPD files. For this purpose, the YaST printer configuration generates a database from the vendor and model information extracted from the PPD files.

The configuration using only PPD files and no other information sources has the advantage that the PPD files in /usr/share/cups/model can be modified freely. For example, if you have PostScript printers the PPD files can be copied directly to /usr/share/cups/model (if they do not already exist in the manufacturer-PPDs or OpenPrintingPPDs-postscript packages) to achieve an optimum configuration for your printers.

Additional PPD files are provided by the following packages:

  • gutenprint: the Gutenprint driver and its matching PPDs

  • splix: the SpliX driver and its matching PPDs

  • OpenPrintingPPDs-ghostscript: PPDs for Ghostscript built-in drivers

  • OpenPrintingPPDs-hpijs: PPDs for the HPIJS driver for non-HP printers

7.8 Troubleshooting Edit source

The following sections cover the most frequently encountered printer hardware and software problems and ways to solve or circumvent these problems. Among the topics covered are GDI printers, PPD files and port configuration. Common network printer problems, defective printouts, and queue handling are also addressed.

7.8.1 Printers without standard printer language support Edit source

These printers do not support any common printer language and can only be addressed with special proprietary control sequences. Therefore they can only work with the operating system versions for which the manufacturer delivers a driver. GDI is a programming interface developed by Microsoft* for graphics devices. Usually the manufacturer delivers drivers only for Windows, and since the Windows driver uses the GDI interface these printers are also called GDI printers. The actual problem is not the programming interface, but that these printers can only be addressed with the proprietary printer language of the respective printer model.

Certain GDI printers can be switched to operate either in GDI mode or in one of the standard printer languages. Check the manual of the printer to see whether this is possible. Specific models require special Windows software to do the switch. For example, the Windows printer driver may always switch the printer back into GDI mode when printing from Windows. For other GDI printers there are extension modules for a standard printer language available.

Several manufacturers provide proprietary drivers for their printers. The disadvantage of proprietary printer drivers is that there is no guarantee that these work with the installed print system or that they are suitable for the multiple hardware platforms. In contrast, printers that support a standard printer language do not depend on a special print system version or a special hardware platform.

Instead of spending time trying to make a proprietary Linux driver work, it may be more cost-effective to purchase a printer which supports a standard printer language (preferably PostScript). This would solve the driver problem once and for all, eliminating the need to install and configure special driver software and obtain driver updates that may be required because of new developments in the print system.

7.8.2 No suitable PPD file available for a PostScript printer Edit source

If the manufacturer-PPDs or OpenPrintingPPDs-postscript packages do not contain a suitable PPD file for a PostScript printer, it should be possible to use the PPD file from the driver CD of the printer manufacturer or download a suitable PPD file from the Web page of the printer manufacturer.

If the PPD file is provided as a zip archive (.zip) or a self-extracting zip archive (.exe), unpack it with unzip. First, review the license terms of the PPD file. Then use the cupstestppd utility to check if the PPD file complies with Adobe PostScript Printer Description File Format Specification, version 4.3. If the utility returns FAIL, the errors in the PPD files are serious and cause major problems. The problem spots reported by cupstestppd should be eliminated. If necessary, ask the printer manufacturer for a suitable PPD file.

7.8.3 Network printer connections Edit source

Identifying network problems

Connect the printer directly to the computer. For test purposes, configure the printer as a local printer. If this works, the problems are related to the network.

Checking the TCP/IP network

The TCP/IP network and name resolution must be functional.

Checking a remote lpd

Use the following command to test if a TCP connection can be established to lpd (port 515) on HOST:

> netcat -z HOST 515 && echo ok || echo failed

If the connection to lpd cannot be established, lpd may not be active or there may be basic network problems.

Provided that the respective lpd is active and the host accepts queries, run the following command as root to query a status report for QUEUE on remote HOST:

# echo -e "\004queue" \
| netcat -w 2 -p 722 HOST 515

If lpd does not respond, it may not be active or there may be basic network problems. If lpd responds, the response should show why printing is not possible on the queue on host. If you receive a response like that shown in Example 7.1, “Error message from lpd, the problem is caused by the remote lpd.

Example 7.1: Error message from lpd
lpd: your host does not have line printer access
lpd: queue does not exist
printer: spooling disabled
printer: printing disabled
Checking a remote cupsd

A CUPS network server can broadcast its queues by default every 30 seconds on UDP port 631. Accordingly, the following command can be used to test whether there is a broadcasting CUPS network server in the network. Make sure to stop your local CUPS daemon before executing the command.

> netcat -u -l -p 631 & PID=$! ; sleep 40 ; kill $PID

If a broadcasting CUPS network server exists, the output appears as shown in Example 7.2, “Broadcast from the CUPS network server”.

Example 7.2: Broadcast from the CUPS network server
ipp://192.168.2.202:631/printers/queue

The following command can be used to test if a TCP connection can be established to cupsd (port 631) on HOST:

> netcat -z HOST 631 && echo ok || echo failed

If the connection to cupsd cannot be established, cupsd may not be active or there may be basic network problems. lpstat -h HOST -l -t returns a status report for all queues on HOST, provided the respective cupsd is active and the host accepts queries.

The next command can be used to test if the QUEUE on HOST accepts a print job consisting of a single carriage-return character. Nothing should be printed. A blank page may be ejected.

> echo -en "\r" \
| lp -d queue -h HOST
Troubleshooting a Network Printer or Print Server Machine

Spoolers running in a print server machine sometimes cause problems when they need to deal with multiple print jobs. Since this is caused by the spooler in the print server machine, there no way to resolve this issue. As a work-around, circumvent the spooler in the print server machine by addressing the printer connected to the print server machine directly with the TCP socket. See Section 7.4, “Network printers”.

In this way, the print server machine is reduced to a converter between the multiple forms of data transfer (TCP/IP network and local printer connection). To use this method, you need to know the TCP port on the print server machine. If the printer is connected to the print server machine and turned on, this TCP port can normally be determined with the nmap utility from the nmap package certain time after the print server machine is powered up. For example, nmap  IP-address may deliver the following output for a print server machine:

Port       State       Service
23/tcp     open        telnet
80/tcp     open        http
515/tcp    open        printer
631/tcp    open        cups
9100/tcp   open        jetdirect

This output indicates that the printer connected to the print server machine can be addressed via TCP socket on port 9100. By default, nmap only checks several commonly known ports listed in /usr/share/nmap/nmap-services. To check all possible ports, use the command nmap -p  FROM_PORT-TO_PORT IP_ADDRESS. For further information, refer to the man page of nmap.

Enter a command like

> echo -en "\rHello\r\f" | netcat -w 1 IP-address port
cat file | netcat -w 1 IP-address port

to send character strings or files directly to the respective port to test if the printer can be addressed on this port.

7.8.4 Defective printouts without error message Edit source

For the print system, the print job is completed when the CUPS back-end completes the data transfer to the recipient (printer). If further processing on the recipient fails (for example, if the printer is not able to print the printer-specific data) the print system does not notice this. If the printer cannot print the printer-specific data, select a PPD file that is more suitable for the printer.

7.8.5 Disabled queues Edit source

If the data transfer to the recipient fails entirely after several attempts, the CUPS back-end, such as USB or socket, reports an error to the print system (to cupsd). The back-end determines how many unsuccessful attempts are appropriate until the data transfer is reported as impossible. As further attempts would be in vain, cupsd disables printing for the respective queue. After eliminating the cause of the problem, the system administrator must re-enable printing with the command cupsenable.

7.8.6 CUPS browsing: deleting print jobs Edit source

If a CUPS network server broadcasts its queues to the client hosts via browsing and a suitable local cupsd is active on the client hosts, the client cupsd accepts print jobs from applications and forwards them to the cupsd on the server. When cupsd on the server accepts a print job, it is assigned a new job number. Therefore, the job number on the client host is different from the job number on the server. As a print job is usually forwarded immediately, it cannot be deleted with the job number on the client host This is because the client cupsd regards the print job as completed when it has been forwarded to the server cupsd.

To delete the print job on the server, use a command such as lpstat -h cups.example.com -o to determine the job number on the server. This assumes that the server has not already completed the print job by sending it to the printer. Use the obtained job number to delete the print job on the server as follows:

> cancel -h cups.example.com QUEUE-JOBNUMBER

7.8.7 Defective print jobs and data transfer errors Edit source

If you switch the printer off or shut down the computer during the printing process, print jobs remain in the queue. Printing resumes when the computer (or the printer) is switched back on. Defective print jobs must be removed from the queue with cancel.

If a print job is corrupted or an error occurs in the communication between the host and the printer, the printer cannot process the data correctly and prints numerous sheets of paper with unintelligible characters. To fix the problem, follow these steps:

  1. To stop printing, remove all paper from ink jet printers or open the paper trays of laser printers. High-quality printers have a button for canceling the current printout.

  2. The print job may still be in the queue, because jobs are only removed after they are sent to the printer. Use lpstat -o or lpstat -h cups.example.com -o to check which queue is currently printing. Delete the print job with cancel QUEUE-JOBNUMBER or cancel -h cups.example.com QUEUE-JOBNUMBER.

  3. Certain data may still be transferred to the printer even though the print job has been deleted from the queue. Check if a CUPS back-end process is still running for the respective queue and stop it.

  4. Reset the printer by switching it off for a while. Then insert the paper and turn on the printer.

7.8.8 Debugging CUPS Edit source

Use the following generic procedure to locate problems in CUPS:

  1. Set LogLevel debug in /etc/cups/cupsd.conf.

  2. Stop cupsd.

  3. Remove /var/log/cups/error_log* to avoid having to search through large log files.

  4. Start cupsd.

  5. Repeat the action that led to the problem.

  6. Check the messages in /var/log/cups/error_log* to identify the cause of the problem.

7.8.9 More information Edit source

In-depth information about printing on openSUSE Leap is presented in the openSUSE Support Database at https://en.opensuse.org/Portal:Printing.

8 Accessing file systems with FUSE Edit source

Abstract

FUSE is the acronym for file system in user space. This means you can configure and mount a file system as an unprivileged user. Normally, you need to be root for this task. FUSE alone is a kernel module. Combined with plug-ins, it allows you to extend FUSE to access almost all file systems like remote SSH connections, ISO images, and more.

8.1 Configuring FUSE Edit source

Before you can use FUSE, you need to install the package fuse. Depending which file system you want to use, you need additional plug-ins available as separate packages. For an overview, see Section 8.5, “Available FUSE plug-ins”.

Generally you do not need to configure FUSE. However, it is a good idea to create a directory where all your mount points are combined. For example, you can create a directory ~/mounts and insert your subdirectories for your different file systems there.

8.2 Mounting an NTFS partition Edit source

NTFS, the New Technology File System, is the default file system of Windows. Since under normal circumstances the unprivileged user cannot mount NTFS block devices using the external FUSE library, the process of mounting a Windows partition described below requires root privileges.

  1. Become root and install the package ntfs-3g.

  2. Create a directory that is to be used as a mount point, for example, ~/mounts/windows.

  3. Find out which Windows partition you need. Use YaST and start the partitioner module to see which partition belongs to Windows, but do not modify anything. Alternatively, become root and execute /sbin/fdisk -l. Look for partitions with a partition type of HPFS/NTFS.

  4. Mount the partition in read-write mode. Replace the placeholder DEVICE with your respective Windows partition:

    > ntfs-3g /dev/DEVICE MOUNT POINT

    To use your Windows partition in read-only mode, append -o ro:

    > ntfs-3g /dev/DEVICE MOUNT POINT -o ro

    The command ntfs-3g uses the current user (UID) and group (GID) to mount the given device. To set the write permissions to a different user, use the command id USER to get the output of the UID and GID values. Set it with:

    # id tux
    uid=1000(tux) gid=100(users) groups=100(users),16(dialout),33(video)
    ntfs-3g /dev/DEVICE MOUNT POINT -o uid=1000,gid=100

    Find additional options in the man page.

To unmount the resource, run fusermount -u MOUNT POINT.

8.3 Mounting remote file system with SSHFS Edit source

SSH, the secure shell network protocol, can be used to exchange data between two computers using a secure channel. To establish an SSH connection through FUSE, proceed as follows:

  1. Install the package sshfs.

  2. Create a directory that is to be used as a mount point. A good idea is to use ~/mounts/HOST. Replace HOST with the name of your remote computer.

  3. Mount the remote file system:

    # sshfs USER@HOST MOUNT POINT
  4. Enter your password for the remote computer.

To unmount the resource, run fusermount -u MOUNT POINT.

8.4 Mounting an ISO file system Edit source

To look into an ISO image, you can mount it with the fuseiso package:

  1. Install the package fuseiso.

  2. Create a directory that is to be used as a mount point, for example, ~/mounts/iso.

  3. Mount the ISO image:

    # fuseiso ISO_IMAGE MOUNT POINT

You can only read content from the ISO image, but you can not write back. To unmount the resource, use fusermount -u MOUNT POINT.

8.5 Available FUSE plug-ins Edit source

FUSE is dependent on plug-ins. The following table lists common plug-ins.

Table 8.1: Available FUSE plug-ins

curlftpfs

mount FTP servers

encfs

mount encrypted file systems

fuseiso

mounts CD-ROM images with ISO9660 file systems in them

fusepod

mount iPods

fusesmb

mount browseable Samba clients or Windows shares

gphotofs

mount supported digital cameras through gPhoto

ntfs-3g

mount NTFS volumes (with read and write support)

obexfs

mount Bluetooth devices

sshfs

file system client based on SSH file transfer protocol

wdfs

mount WebDAV file systems

8.6 More information Edit source

For more information, see the home page of FUSE at https://github.com/libfuse/libfuse.

Part III Managing and updating software Edit source

9 Installing or removing software

Using YaST's software management module, you can search for software packages as well as install and remove them. When installing packages, YaST automatically resolves all dependencies. To install packages that are not on the installation medium, you can add software repositories and YaST to manage them. You can also keep your system up to date by managing software updates using the update applet.

10 Installing add-on products

Add-on products are system extensions. You can install a third party add-on product or a special system extension of openSUSE® Leap (for example, a CD with support for additional languages or a CD with binary drivers). To install a new add-on, start YaST and select Software › Add-On Products. You can select various types of product media, like CD, FTP, USB mass storage devices (such as USB flash drives or disks) or a local directory. You can also work directly with ISO files. To add an add-on as ISO file medium, select Local ISO Image then enter the Path to ISO Image. The Repository Name is arbitrary.

11 YaST online update

SUSE offers a continuous stream of software security updates for your product. By default, the update applet is used to keep your system up to date. Refer to Section 9.4, “The GNOME package updater” for further information on the update applet. This chapter covers the alternative tool for updating s…

12 Upgrading the system and system changes

You can upgrade an existing system without completely reinstalling it. There are two types of renewing the system or parts of it: updating individual software packages and upgrading the entire system. Updating individual packages is covered in Chapter 9, Installing or removing software and Chapter 11, YaST online update. Two ways to upgrade the system are discussed in the following sections— see Section 12.1.3, “Upgrading with YaST” and Section 12.1.4, “Distribution upgrade with Zypper”.

9 Installing or removing software Edit source

Abstract

Using YaST's software management module, you can search for software packages as well as install and remove them. When installing packages, YaST automatically resolves all dependencies. To install packages that are not on the installation medium, you can add software repositories and YaST to manage them. You can also keep your system up to date by managing software updates using the update applet.

The YaST Software Manager makes it possible to manage software sources on your system. There are two versions of this YaST module: a graphical version for X Window and a text-based version to use with the command line. The graphical flavor is described below—for details on the text-based YaST, see Book “Reference”, Chapter 1 “YaST in text mode”.

Note
Note: Confirmation and review of changes

When installing, updating or removing packages, any changes in the Software Manager are only applied after clicking Accept or Apply. YaST maintains a list with all actions, allowing you to review and modify your changes before applying them to the system.

9.1 Definition of terms Edit source

The following terms are important for understanding installing and removing software in openSUSE Leap.

Repository

A local or remote directory containing packages, plus additional information about these packages (package metadata).

(Repository) alias/repository name

A short name for a repository (called Alias within Zypper and Repository Name within YaST). It can be chosen by the user when adding a repository and must be unique.

Repository description files

Each repository provides files describing content of the repository (package names, versions, etc.). These repository description files are downloaded to a local cache that is used by YaST.

Product

Represents a whole product, for example, openSUSE® Leap.

Pattern

A pattern is an installable group of packages dedicated to a certain purpose. For example, the Laptop pattern contains all packages that are needed in a mobile computing environment. Patterns define package dependencies (such as required or recommended packages) and come with a preselection of packages marked for installation. This ensures that the most important packages needed for a certain purpose are available on your system after installation of the pattern. If necessary, you can manually select or deselect packages within a pattern.

Package

A package is a compressed file in rpm format that contains the files for a particular program.

Patch

A patch consists of one or more packages and may be applied by delta RPMs. It may also introduce dependencies to packages that are not installed yet.

Resolvable

A generic term for product, pattern, package or patch. The most commonly used type of resolvable is a package or a patch.

Delta RPM

A delta RPM consists only of the binary diff between two defined versions of a package, and therefore has the smallest download size. Before being installed, the full RPM package is rebuilt on the local machine.

Package dependencies

Certain packages are dependent on other packages, such as shared libraries. In other terms, a package may require other packages—if the required packages are not available, the package cannot be installed. Besides dependencies (package requirements) that must be fulfilled, certain packages recommend other packages. These recommended packages are only installed if they are available, otherwise they are ignored and the package recommending them is installed nevertheless.

9.2 Using the YaST software manager Edit source

Start the software manager from the YaST Control Center by choosing Software › Software Management.

YaST software manager screen

9.2.2 Installing and removing packages or patterns Edit source

Certain packages are dependent on other packages, such as shared libraries. Several packages cannot coexist with others on the system. If possible, YaST automatically resolves these dependencies or conflicts. If your choice results in a dependency conflict that cannot be automatically solved, you need to solve it manually as described in Section 9.2.4, “Package dependencies”.

Note
Note: Removal of packages

When removing any packages, by default YaST only removes the selected packages. If you want YaST to also remove any other packages that become unneeded after removal of the specified package, select Options › Cleanup when deleting packages from the main menu.

  1. Search for packages as described in Section 9.2.1, “Searching software”.

  2. The packages found are listed in the right pane. To install a package or remove it, right-click it and choose Install or Delete. If the relevant option is not available, check the package status indicated by the symbol in front of the package name—press ShiftF1 for help.

    Tip
    Tip: Applying an action to all packages listed

    To apply an action to all packages listed in the right pane, go to the main menu and choose an action from Package › All in This List.

  3. To install a pattern, right-click the pattern name and choose Install.

  4. It is not possible to remove a pattern. Instead, select the packages for the pattern you want to remove and mark them for removal.

  5. To select more packages, repeat the steps mentioned above.

  6. Before applying your changes, you can review or modify them by clicking View › Installation Summary. By default, all packages that will change status are listed.

  7. To revert the status for a package, right-click the package and select one of the following entries: Keep if the package was scheduled to be deleted or updated, or Do Not Install if it was scheduled for installation. To abandon all changes and quit the Software Manager, click Cancel and Abandon.

  8. When you are finished, click Accept to apply your changes.

  9. If YaST finds additional dependencies, it shows a list of related packages to install, update or remove. Click Continue to accept them.

    After all selected packages are installed, updated or removed, the YaST Software Manager automatically closes.

Note
Note: Installing source packages

Installing source packages with YaST Software Manager is not possible at the moment. Use the command line tool zypper for this purpose. For more information, see Book “Reference”, Chapter 2 “Managing software with command line tools”, Section 2.1.3.5 “Installing or downloading source packages”.

9.2.3 Updating packages Edit source

Instead of updating individual packages, you can also update all installed packages or all packages from a certain repository. When mass updating packages, the following aspects are generally considered:

  • priorities of the repositories that provide the package,

  • architecture of the package (for example, AMD64/Intel 64),

  • version number of the package,

  • package vendor.

Which of the aspects has the highest importance for choosing the update candidates depends on the respective update option you choose.

  1. To update all installed packages to the latest version, choose Package › All Packages › Update if Newer Version Available from the main menu.

    All repositories are checked for possible update candidates, using the following policy: YaST first tries to restrict the search to packages with the same architecture and vendor as the installed one. If the search is positive, the best update candidate from those is selected according to the process below. However, if no comparable package of the same vendor can be found, the search is expanded to all packages with the same architecture. If still no comparable package can be found, all packages are considered and the best update candidate is selected according to the following criteria:

    1. Repository priority: prefer the package from the repository with the highest priority.

    2. If more than one package results from this selection, choose the one with the best architecture (best choice: matching the architecture of the installed one).

    If the resulting package has a higher version number than the installed one, the installed package is updated and replaced with the selected update candidate.

    This option tries to avoid changes in architecture and vendor for the installed packages, but under certain circumstances, they are tolerated.

    Note
    Note: Update unconditionally

    If you choose Package › All Packages › Update Unconditionally instead, the same criteria apply but any candidate package found is installed unconditionally. Thus, choosing this option may lead to downgrading certain packages.

  2. To make sure that the packages for a mass update derive from a certain repository:

    1. Choose the repository from which to update as described in Section 9.2.1, “Searching software” .

    2. On the right hand side of the window, click Switch system packages to the versions in this repository. This explicitly allows YaST to change the package vendor when replacing the packages.

      When you proceed with Accept, all installed packages are replaced by packages deriving from this repository, if available. This may lead to changes in vendor and architecture and even to downgrading certain packages.

    3. To refrain from this, click Cancel switching system packages to the versions in this repository. You can only cancel this until you click the Accept button.

  3. Before applying your changes, you can review or modify them by clicking View › Installation Summary. By default, all packages that will change status, are listed.

  4. If all options are set according to your wishes, confirm your changes with Accept to start the mass update.

9.2.4 Package dependencies Edit source

Most packages are dependent on other packages. If a package, for example, uses a shared library, it is dependent on the package providing this library. Certain packages cannot coexist, causing a conflict (for example, you can only install one mail transfer agent: sendmail or postfix). When installing or removing software, the Software Manager makes sure no dependencies or conflicts remain unsolved to ensure system integrity.

In case there exists only one solution to resolve a dependency or a conflict, it is resolved automatically. Multiple solutions always cause a conflict which needs to be resolved manually. If solving a conflict involves a vendor or architecture change, it also needs to be solved manually. When clicking Accept to apply any changes in the Software Manager, you get an overview of all actions triggered by the automatic resolver which you need to confirm.

By default, dependencies are automatically checked. A check is performed every time you change a package status (for example, by marking a package for installation or removal). This is generally useful, but can become exhausting when manually resolving a dependency conflict. To disable this function, go to the main menu and deactivate Dependencies › Autocheck. Manually perform a dependency check with Dependencies › Check Now. A consistency check is always performed when you confirm your selection with Accept.

To review a package's dependencies, right-click it and choose Show Solver Information. A map showing the dependencies opens. Packages that are already installed are displayed in a green frame.

Note
Note: Manually solving package conflicts

Unless you are experienced, follow the suggestions YaST makes when handling package conflicts, otherwise you may not be able to resolve them. Keep in mind that every change you make potentially triggers other conflicts, so you can easily end up with a steadily increasing number of conflicts. In case this happens, Cancel the Software Manager, Abandon all your changes and start again.

Conflict management of the software manager
Figure 9.1: Conflict management of the software manager

9.2.5 Handling package recommendations Edit source

In addition to the hard dependencies required to run a program (for example a certain library), a package can also have weak dependencies, which add for example extra functionality or translations. These weak dependencies are called package recommendations.

When installing a new package, recommended packages are still installed by default. When updating an existing package, missing recommendations are not be installed automatically. To change this, set PKGMGR_RECOMMENDED="yes" in /etc/sysconfig/yast2. To install all missing recommendations for already installed packages, start YaST › Software Manager and choose Extras › Install All Matching Recommended Packages.

To disable the installation of recommended packages when installing new packages, deactivate Dependencies › Install Recommended Packages in the YaST Software Manager. When using the command-line tool Zypper to install packages, use the option --no-recommends.

9.3 Managing software repositories and services Edit source

To install third-party software, add software repositories to your system. By default, product repositories such as openSUSE Leap-DVD 15.6 and a matching update repository are automatically configured. Depending on the initially selected product, an additional repository containing translations, dictionaries, etc. might also be configured.

To manage repositories, start YaST and select Software › Software Repositories. The Configured Software Repositories dialog opens. Here, you can also manage subscriptions to Services by changing the View at the right corner of the dialog to All Services. A Service in this context is a Repository Index Service (RIS) that can offer one or more software repositories. Such a Service can be changed dynamically by its administrator or vendor.

Each repository provides files describing repository content (package names, versions, etc.). YaST downloads these repository description files to a local cache. To ensure their integrity, software repositories can be signed with the GPG Key of the repository maintainer. Whenever you add a new repository, YaST offers the ability to import its key.

Warning
Warning: Trusting external software sources

Before adding external software repositories to your list of repositories, make sure this repository can be trusted. SUSE is not responsible for any problems arising from software installed from third-party software repositories.

9.3.1 Adding software repositories Edit source

You can either add repositories from DVD/CD, a USB flash drive, a local directory, an ISO image, or a network source.

To add repositories from the Configured Software Repositories dialog in YaST proceed as follows:

  1. Click Add.

  2. Select one of the options listed in the dialog:

    Adding a software repository
    Figure 9.2: Adding a software repository
    • To scan your network for installation servers announcing their services via SLP, select Scan Using SLP and click Next.

    • To add a repository from a removable medium, choose the relevant option and insert the medium or connect the USB device to the machine, respectively. Click Next to start the installation.

    • For the majority of repositories, you will be asked to specify the path (or URL) to the media after selecting the respective option and clicking Next. Specifying a Repository Name is optional. If none is specified, YaST will use the product name or the URL as repository name.

    The option Download Repository Description Files is activated by default. If you deactivate the option, YaST will automatically download the files later, if needed.

  3. Depending on the repository you add, you may be prompted to import the repository's GPG key or asked to agree to a license.

    After confirming, YaST will download and parse the metadata. It will add the repository to the list of Configured Repositories.

  4. If needed, adjust the repository Properties as described in Section 9.3.2, “Managing repository properties”.

  5. Confirm your changes with OK to close the configuration dialog.

  6. After having successfully added the repository, the software manager starts and you can install packages from this repository. For details, refer to Chapter 9, Installing or removing software.

9.3.2 Managing repository properties Edit source

The Configured Software Repositories overview of the Software Repositories lets you change the following repository properties:

Status

The repository status can either be Enabled or Disabled. You can only install packages from repositories that are enabled. To turn a repository off temporarily, select it and deactivate Enable. You can also double-click a repository name to toggle its status. To remove a repository completely, click Delete.

Refresh

When refreshing a repository, its content description (package names, versions, etc.) is downloaded to a local cache that is used by YaST. It is sufficient to do this once for static repositories such as CDs or DVDs, whereas repositories whose content changes often should be refreshed frequently. The easiest way to keep a repository's cache up to date is to choose Automatically Refresh. To do a manual refresh click Refresh and select one of the options.

Keep Downloaded Packages

Packages from remote repositories are downloaded before being installed. By default, they are deleted upon successful installation. Activating Keep Downloaded Packages prevents the deletion of downloaded packages. The download location is configured in /etc/zypp/zypp.conf, by default it is /var/cache/zypp/packages.

Priority

The Priority of a repository is a value between 1 and 200, with 1 being the highest priority and 200 the lowest priority. Any new repositories that are added with YaST get a priority of 99 by default. If you do not care about a priority value for a certain repository, you can also set the value to 0 to apply the default priority to that repository (99). If a package is available in more than one repository, then the repository with the highest priority takes precedence. This is useful to avoid downloading packages unnecessarily from the Internet by giving a local repository (for example, a DVD) a higher priority.

Important
Important: Priority compared to version

The repository with the highest priority takes precedence in any case. Therefore, make sure that the update repository always has the highest priority, otherwise you might install an outdated version that will not be updated until the next online update.

Name and URL

To change a repository name or its URL, select it from the list with a single-click and then click Edit.

9.3.3 Managing repository keys Edit source

To ensure their integrity, software repositories can be signed with the GPG Key of the repository maintainer. Whenever you add a new repository, YaST offers to import its key. Verify it as you would do with any other GPG key and make sure it does not change. If you detect a key change, something might be wrong with the repository. Disable the repository as an installation source until you know the cause of the key change.

To manage all imported keys, click GPG Keys in the Configured Software Repositories dialog. Select an entry with the mouse to show the key properties at the bottom of the window. Add, Edit, or Delete keys with a click on the respective buttons.

9.4 The GNOME package updater Edit source

SUSE offers a continuous stream of software security patches and updates for your product. They can be installed using tools available with your desktop or by running the YaST online update module. This section describes how to update the system from the GNOME desktop using the Package Updater.

Contrary to the YaST Online Update module, the GNOME Package Updater not only offers to install patches from the update repositories, but also new versions of packages that are already installed. (Patches fix security issues or malfunctions; the functionality and version number is usually not changed. New versions of a package increase the version number and add functionality or introduce major changes.)

Whenever new patches or package updates are available, GNOME shows a notification in the notification area or on the lock screen.

Update notification on GNOME desktop
Figure 9.3: Update notification on GNOME desktop

To configure the notification settings for the Package Updater, start GNOME Settings and choose Notifications › Package Updater.

Procedure 9.1: Installing patches and updates with the GNOME package updater
  1. To install the patches and updates, click the notification message. This opens the GNOME Package Updater. Alternatively, open the updater from Activities by typing package U and choosing Package Updater.

  2. Updates are sorted into four categories:

    Security updates (patches)

    Fix severe security hazards and should always be installed.

    Recommended updates (patches)

    Fix issues that could compromise your computer. Installing them is strongly recommended.

    Optional updates (patches)

    Fix non-security relevant issues or provide enhancements.

    Other updates

    New versions of packages that are installed.

    All available updates are preselected for installation. If you do not want to install all updates, deselect unwanted updates first. It is strongly recommended to always install all security and recommended updates.

    To get detailed information on an update, click its title and then Details. The information is displayed in a box beneath the package list.

  3. Click Install Updates to start the installation.

  4. Some updates may require to restart the machine or to log out. Check the message displayed after installation for instructions.

9.5 Updating packages with GNOME Software Edit source

In addition to the GNOME Package Updater, GNOME provides GNOME Software which has the following functionality:

  • Install, update, and remove software delivered as an RPM via PackageKit

  • Install, update, and remove software delivered as a Flatpak

  • Install, update, and remove GNOME shell extensions (https://extensions.gnome.org)

  • Update firmware for hardware devices using Linux Vendor Firmware Service (LVFS, https://fwupd.org)

GNOME Software also provides screenshots, ratings, and reviews for software.

GNOME Software—Updates view
Figure 9.4: GNOME SoftwareUpdates view

GNOME Software has the following differences to other tools provided on openSUSE Leap:

  • Unlike YaST or Zypper, for installing software packaged as an RPM, GNOME Software is restricted to software that provides AppStream metadata. This includes most desktop applications.

  • While the GNOME Package Updater updates packages within the running system (forcing you to restart the respective applications), GNOME Software downloads the updates and applies them after reboot.

10 Installing add-on products Edit source

Abstract

Add-on products are system extensions. You can install a third party add-on product or a special system extension of openSUSE® Leap (for example, a CD with support for additional languages or a CD with binary drivers). To install a new add-on, start YaST and select Software › Add-On Products. You can select various types of product media, like CD, FTP, USB mass storage devices (such as USB flash drives or disks) or a local directory. You can also work directly with ISO files. To add an add-on as ISO file medium, select Local ISO Image then enter the Path to ISO Image. The Repository Name is arbitrary.

10.1 Add-ons Edit source

To install a new add-on, proceed as follows:

  1. In YaST select Software › Add-On Products to see an overview of already installed add-on products.

  2. To install a new add-on product, click Add.

  3. From the list of available Media Types specify the type matching your repository.

  4. To add a repository from a removable medium, choose the relevant option and insert the medium or connect the USB device to the machine, respectively.

  5. You can choose to Download Repository Description Files now. If the option is deselected, YaST will automatically download the files later, if needed. Click Next to proceed.

  6. When adding a repository from the network, enter the data you are prompted for. Continue with Next.

  7. Depending on the repository you have added, you may be asked if you want to import the GPG key with which it is signed or asked to agree to a license.

    After confirming these messages, YaST will download and parse the metadata and add the repository to the list of Configured Repositories..

  8. If needed, adjust the repository Properties as described in Section 9.3.2, “Managing repository properties” or confirm your changes with OK to close the configuration dialog.

  9. After having successfully added the repository for the add-on media, the software manager starts and you can install packages. Refer to Chapter 9, Installing or removing software for details.

10.2 Binary drivers Edit source

Some hardware needs binary-only drivers to function properly. If you have such hardware, refer to the release notes for more information about availability of binary drivers for your system. To read the release notes, open YaST and select Miscellaneous › Release Notes.

11 YaST online update Edit source

SUSE offers a continuous stream of software security updates for your product. By default, the update applet is used to keep your system up to date. Refer to Section 9.4, “The GNOME package updater” for further information on the update applet. This chapter covers the alternative tool for updating software packages: YaST Online Update.

The current patches for openSUSE® Leap are available from an update software repository, which is automatically configured during the installation. Alternatively, you can manually add an update repository from a source you trust. To add or remove repositories, start the Repository Manager with Software › Software Repositories in YaST. Learn more about the Repository Manager in Section 9.3, “Managing software repositories and services”.

SUSE provides updates with different relevance levels:

Security updates

Fix severe security hazards and should always be installed.

Recommended updates

Fix issues that could compromise your computer.

Optional updates

Fix non-security relevant issues or provide enhancements.

11.1 The online update dialog Edit source

To open the YaST Online Update dialog, start YaST and select Software  › Online Update. Alternatively, start it from the command line with yast2 online_update.

The Online Update window consists of four sections.

YaST online update
Figure 11.1: YaST online update

The Summary section on the left lists the available patches for openSUSE Leap. The patches are sorted by security relevance: security, recommended, and optional. You can change the view of the Summary section by selecting one of the following options from Show Patch Category:

Needed patches (default view)

Non-installed patches that apply to packages installed on your system.

Unneeded patches

Patches that either apply to packages not installed on your system, or patches that have requirements which have already have been fulfilled (because the relevant packages have already been updated from another source).

All patches

All patches available for openSUSE Leap.

Each list entry in the Summary section consists of a symbol and the patch name. For an overview of the possible symbols and their meaning, press ShiftF1. Actions required by Security and Recommended patches are automatically preset. These actions are Autoinstall, Autoupdate and Autodelete.

If you install an up-to-date package from a repository other than the update repository, the requirements of a patch for this package may be fulfilled with this installation. In this case, a check mark is displayed in front of the patch summary. The patch is visible in the list until you mark it for installation. This does not install the patch (because the package already is up to date), but mark the patch as having been installed.

Select an entry in the Summary section to view a short Patch Description at the bottom left corner of the dialog. The upper right section lists the packages included in the selected patch (a patch can consist of several packages). Click an entry in the upper right section to view details about the respective package that is included in the patch.

11.2 Installing patches Edit source

The YaST Online Update dialog allows you to either install all available patches at once or manually select the desired patches. You may also revert patches that have been applied to the system.

By default, all new patches (except optional ones) that are currently available for your system are already marked for installation. They will be applied automatically once you click Accept or Apply. If one or multiple patches require a system reboot, you will be notified about this before the patch installation starts. You can then either decide to continue with the installation of the selected patches, skip the installation of all patches that need rebooting and install the rest, or go back to the manual patch selection.

Procedure 11.1: Applying patches with YaST online update
  1. Start YaST and select Software › Online Update.

  2. To automatically apply all new patches (except optional ones) that are currently available for your system, click Apply or Accept.

  3. First modify the selection of patches that you want to apply:

    1. Use the respective filters and views that the interface provides. For details, refer to Section 11.1, “The online update dialog”.

    2. Select or deselect patches according to your needs and wishes by right-clicking the patch and choosing the respective action from the context menu.

      Important
      Important: Always apply security updates

      Do not deselect any security-related patches without a good reason. These patches fix severe security hazards and prevent your system from being exploited.

    3. Most patches include updates for several packages. To change actions for single packages, right-click a package in the package view and choose an action.

    4. To confirm your selection and apply the selected patches, proceed with Apply or Accept.

  4. After the installation is complete, click Finish to leave the YaST Online Update. Your system is now up to date.

11.3 Viewing retracted patches Edit source

Maintenance updates are carefully tested to minimize the risk of introducing a bug. If a patch proves to contain a bug, it is automatically retracted. A new update (with a higher version number) is issued to revert the buggy patch, and is blocked from being installed again. You can see retracted patches, and their history, on the Package Classification tab.

Viewing retracted patches and history
Figure 11.2: Viewing retracted patches and history

11.4 Automatic online update Edit source

You may configure automatic updates with a daily, weekly or monthly schedule with YaST. Install the yast2-online-update-configuration package.

By default, updates are downloaded as delta RPMs. Since rebuilding RPM packages from delta RPMs is a memory- and processor-intensive task, certain setups or hardware configurations may require you to disable the use of delta RPMs for the sake of performance.

Certain patches, such as kernel updates or packages requiring license agreements, require user interaction, which would cause the automatic update procedure to stop. You can configure skipping patches that require user interaction.

Use the Patches tab in the YaST Software module to review available and installed patches, including references to bug reports and CVE bulletins.

Procedure 11.2: Configuring the automatic online update
  1. After installation, start YaST and select Software › Online Update. Choose Configuration › Online Update. If the yast2-online-update-configuration is not installed, you will be prompted to do that.

    YaST online update configuration
    Figure 11.3: YaST online update configuration

    Alternatively, start the module with yast2 online_update_configuration from the command line.

  2. Choose the update interval: Daily, Weekly, or Monthly.

  3. Sometimes patches may require the attention of the administrator, for example when restarting critical services. For example, this might be an update for Docker Open Source Engine that requires all containers to be restarted. Before these patches are installed, the user is informed about the consequences and is asked to confirm the installation of the patch. Such patches are called Interactive Patches.

    When installing patches automatically, it is assumed that you have accepted the installation of interactive patches. If you prefer to review these patches before they get installed, check Skip Interactive Patches. In this case, interactive patches will be skipped during automated patching. Make sure to periodically run a manual online update, to check whether interactive patches are waiting to be installed.

  4. To automatically accept any license agreements, activate Agree with Licenses.

  5. To automatically install all packages recommended by updated packages, activate Include Recommended Packages.

  6. To disable the use of delta RPMs (for performance reasons), un-check Use Delta RPMs.

  7. To filter the patches by category (such as security or recommended), check Filter by Category and add the appropriate patch categories from the list. Only patches of the selected categories will be installed. It is a good practice to enable only automatic Security updates, and to manually review all others. Patching is normally reliable, but you may wish to test non-security patches, and roll them back if you encounter any problems.

    • Packagemanager and YaST supply patches for package management and YaST features and modules.

    • Security patches provide crucial updates and bugfixes.

    • Recommended patches are optional bugfixes and enhancements.

    • Optional are new packages.

    • Other is equivalent to miscellaneous.

    • Document is unused.

  8. Confirm your configuration by clicking OK.

The automatic online update does not automatically restart the system afterward. If there are package updates that require a system reboot, you need to do this manually.

12 Upgrading the system and system changes Edit source

Abstract

You can upgrade an existing system without completely reinstalling it. There are two types of renewing the system or parts of it: updating individual software packages and upgrading the entire system. Updating individual packages is covered in Chapter 9, Installing or removing software and Chapter 11, YaST online update. Two ways to upgrade the system are discussed in the following sections— see Section 12.1.3, “Upgrading with YaST” and Section 12.1.4, “Distribution upgrade with Zypper”.

12.1 Upgrading the system Edit source

Important
Important: openSUSE Leap 15.6 is only available as 64-bit version

openSUSE Leap 15.6 is only available as 64-bit version. Upgrading 32-bit installations to 64-bit is not supported. Please follow the instructions in Chapter 1, Installation Quick Start and Chapter 3, Installation steps to install openSUSE Leap on your computer or consider switching to openSUSE Tumbleweed.

The release notes are bundled in the installer, and you may also read them online at openSUSE Leap Release Notes.

Software tends to grow from version to version. Therefore, take a look at the available partition space with df before updating. If you suspect you are running short of disk space, secure your data before you update and repartition your system. There is no general rule regarding how much space each partition should have. Space requirements depend on your particular partitioning profile, the software selected, and the version numbers of the system.

12.1.1 Preparations Edit source

Before upgrading, copy the old configuration files to a separate medium (such as removable hard disk or USB flash drive) to secure the data. This primarily applies to files stored in /etc as well as some of the directories and files in /var. You may also want to write the user data in /home (the HOME directories) to a backup medium. Back up this data as root. Only root has read permission for all local files.

Before starting your update, make note of the root partition. The command df / lists the device name of the root partition. In Example 12.1, “List with df -h, the root partition to write down is /dev/sda3 (mounted as /).

Example 12.1: List with df -h
Filesystem     Size  Used Avail Use% Mounted on
/dev/sda3       74G   22G   53G  29% /
udev           252M  124K  252M   1% /dev
/dev/sda5      116G  5.8G  111G   5% /home
/dev/sda1       39G  1.6G   37G   4% /windows/C
/dev/sda2      4.6G  2.6G  2.1G  57% /windows/D

12.1.2 Possible problems Edit source

If you upgrade a default system from the previous version to this version, YaST works out the necessary changes and performs them. Depending on your customization, some steps (or the entire upgrade procedure) may fail and you must resort to copying back your backup data. Check the following issues before starting the system update.

12.1.2.1 Checking passwd and group in /etc Edit source

Before upgrading the system, make sure that /etc/passwd and /etc/group do not contain any syntax errors. For this purpose, start the verification utilities pwck and grpck as root to eliminate any reported errors.

12.1.2.2 Shut down virtual machines Edit source

If your machine serves as a VM Host Server for KVM or Xen, make sure to properly shut down all running VM Guests prior to the update. Otherwise you may not be able to access the guests after the update.

12.1.2.3 PostgreSQL Edit source

Before updating PostgreSQL (postgres), dump the databases. See the manual page of pg_dump. This is only necessary if you actually used PostgreSQL prior to your update.

12.1.3 Upgrading with YaST Edit source

Following the preparation procedure outlined in Section 12.1.1, “Preparations”, you can now upgrade your system:

  1. Insert the openSUSE Leap DVD into the drive, then reboot the computer to start the installation program. On machines with a traditional BIOS you will see the graphical boot screen shown below. On machines equipped with UEFI, a slightly different boot screen is used. Secure boot on UEFI machines is supported.

    Use F2 to change the language for the installer. A corresponding keyboard layout is chosen automatically. See Section 2.2.1, “The boot screen on machines with traditional BIOS” or Section 2.2.2, “The boot screen on machines equipped with UEFI” for more information about changing boot parameters.

  2. Select Upgrade on the boot screen, then press Enter. This boots the system and loads the openSUSE Leap installer. Do not select Installation.

  3. The Language and Keyboard Layout are initialized with the language settings you have chosen on the boot screen. Change them here, if necessary.

    Read the License Agreement. It is presented in the language you have chosen on the boot screen. License Translations are available. Proceed with Next.

  4. YaST determines if there are multiple root partitions. If there is only one, continue with the next step. If there are several, select the right partition and confirm with Next (/dev/sda3 was selected in the example in Section 12.1.1, “Preparations”). YaST reads the old fstab on this partition to analyze and mount the file systems listed there.

    Tip
    Tip: Release notes

    From this point on, the Release Notes can be viewed from any screen during the installation process by selecting Release Notes.

  5. YaST shows a list of Previously Used Repositories. By default all repositories will get removed. If you had not added any custom repositories, do not change the settings. The packages for the upgrade will be installed from DVD and you can optionally enable the default online repositories can be chosen in the next step.

    If you have had added custom repositories, for example from the openSUSE Build Service, you have two choices:

    • Leave the repository in state Removed. Software that was installed from this repository will get removed during the upgrade. Use this method if no version of the repository that matches the new openSUSE Leap version, is available.

    • Update and enable the repository. Use this method if a version that matches the new openSUSE Leap version is available for the repository. Change it's URL by clicking the repository in the list and then Change. Enable the repository afterwards by clicking Toggle Status until it is set to Enable.

    Do not use repositories matching the previous version unless you are absolutely sure they will also work with the new openSUSE version. If not, the system may be unstable or not work at all.

  6. In case an Internet connection is available, you may now activate optional online repositories. Please enable all repositories you had enable before to ensure all packages get upgraded correctly. Enabling the update repositories is strongly recommended—this will ensure that you get the latest package versions available, including ll security updates and fixes.

    After having proceeded with Next, you need to confirm the license agreement for the online repositories with Next.

  7. Use the Installation Settings screen to review and—if necessary—change several proposed installation settings. The current configuration is listed for each setting. To change it, click the headline.

    System

    View detailed hardware information by clicking System. In the resulting screen you can also change Kernel Settings—see Section 3.11.7, “System for more information.

    Update options

    By default, YaST will update perform full Update with Installation of New Software and Features based on a selection of patterns. Each pattern contains several software packages needed for specific functions (for example, Web and LAMP server or a print server).

    Here you can change the package selection or change the Update Mode to Only Update Installed Packages.

    Packages

    You can further tweak the package selection on the Packages screen. Here you can not only select patterns but also list their contents and search for individual packages. See Chapter 9, Installing or removing software for more information.

    If you intend to enhance your system, it is recommended to finish the upgrade first and then install additional software.

    Backup

    You also have the possibility to make backups of various system components. Selecting backups slows down the upgrade process. Use this option if you do not have a recent system backup.

    Language

    This section allows you to change the Primary Language and configure additional Secondary Languages. Optionally, you can adjust the keyboard layout and timezone to the selected primary language.

    Keyboard layout

    Here you can change the keyboard layout and adjust additional Expert Keyboard Settings.

    Booting

    This section shows the boot loader configuration. Changing the defaults is only recommended if really needed. Refer to Book “Reference”, Chapter 12 “The boot loader GRUB 2” for details.

  8. After you have finalized the system configuration on the Installation Settings screen, click Update. Depending on your software selection you may need to agree to license agreements before the installation confirmation screen pops up. Up to this point no changes have been made to your system. After you click Update a second time, the upgrade process starts.

Once the basic upgrade installation is finished, YaST reboots the system. Finally, YaST updates the remaining software, if any and displays the release notes, if wanted.

12.1.4 Distribution upgrade with Zypper Edit source

With the zypper command line utility you can upgrade to the next version of the distribution. Most importantly, you can initiate the system upgrade process from within the running system.

This feature is attractive for advanced users who want to run remote upgrades or upgrades on many similarly configured systems.

12.1.4.1 Preparing the upgrade with Zypper Edit source

To avoid unexpected errors during the upgrade process using zypper, minimize risky constellations.

  • Quit as many applications and stop unneeded services as possible and log out all regular users.

  • Disable third-party repositories before starting the upgrade, or lower the priority of these repositories to make sure packages from the default system repositories will get preference. Enable them again after the upgrade and edit their version string to match the version number of the distribution of the upgraded now running system.

12.1.4.2 The upgrade procedure Edit source

Warning
Warning: Check your system backup

Before actually starting the upgrade procedure, check that your system backup is up-to-date and restorable. This is especially important because you need to enter many of the following steps manually.

The program zypper supports long and short command names. For example, you can abbreviate zypper install as zypper in. In the following text, the short variants are used.

  1. Run the online update to make sure the software management stack is up-to-date:

    > sudo zypper patch
  2. Configure the repositories you want to use as update sources. Getting this right is crucial. The NAME of the repositories used in the following steps may vary depending on the customization of your OS. For more info, refer to Book “Reference”, Chapter 2 “Managing software with command line tools”, Section 2.1.6 “Managing repositories with Zypper”)

    To view your current repositories, enter:

    > zypper --releasever=15.6 lr -u
  3. In the result of the previous command, check the last column (URL). All repository links should contain 15.6 as version number. If this is not the case, the version number is missing or hard-coded in the repository definition file under /etc/zypp/repos.d/. To fix this, proceed as follows:

    1. Decide whether the repository is still needed. If not, delete it:

      > sudo zypper rr NAME

      Delete all repositories you no longer need.

    2. For third-party repositories without a version number, check with the repository provider whether openSUSE Leap 15.6 is supported. If so, keep the repository. If not, delete it as described above.

    3. All remaining repositories you want to keep need to be updated to the new version. To allow for future updates without repository modifications, replace the hard-coded version number with the variable $releasever. If 15.3 is hard-coded, run:

      > sudo sed -i 's/15.3/$releasever/' /etc/zypp/repos.d/*.repo

      Repeat this step for every hard-coded version number.

      Use your browser to check whether the new repository URL is correct. If not, a new version of the repository may not exist yet. Deactivate the repository and try again later.

      > sudo zypper mr -d NAME

      Packages from deactivated repositories will not be removed if all dependencies are still fulfilled.

  4. Finally, check the current repository configuration again

    > sudo zypper --releasever=15.6 lr -u

    All repositories should now point to a 15.6 version (except for third-party repositories without versioning that support new releases). Repositories still pointing to an old version should at least be disabled (the column Enabled needs to show No).

  5. Update the repository metadata by running:

    > sudo zypper --releasever=15.6 ref
  6. Start the distribution upgrade that will lift your system to the new version:

    > sudo zypper --releasever=15.6 dup

    Depending on the software selection, you may need to approve one or more licenses. Check the output of the command. If everything is OK, approve with y.

  7. Finally, restart your machine to boot into the new openSUSE Leap version:

    > sudo shutdown -r now

You can upgrade your system by using zypper dup. When using this command, take the following into account:

  • If you are using zypper dup and there is not enough disk space available, the upgrade fails. In this case, use --pkg-cache-dir DIR to set an alternative package cache directory.

  • All packages with unresolved dependencies will be removed. Packages installed from disabled repositories are kept as long as their dependencies are satisfied. Packages that are no longer available in the repositories are considered orphaned. Such packages are uninstalled if their dependencies cannot be satisfied. If they can be satisfied, such packages stay installed.

  • zypper dup ensures that all installed packages come from one of the available repositories. It does not consider the version or architecture, but prevents changing the vendor of the installed packages by default, using the --no-allow-vendor-change option. If you have third-party repositories enabled, some repositories may break during the upgrade. In this case, use --allow-vendor-change instead.

12.1.5 Updating individual packages Edit source

Regardless of your overall updated environment, you can always update individual packages. From this point on, however, it is your responsibility to ensure that your system remains consistent.

Use the YaST software management tool to update packages as described in Chapter 9, Installing or removing software. Select components from the YaST package selection list according to your needs. If a newer version of a package exists, the version numbers of the installed and the available versions are listed in blue color in the Installed (Available) column. If you select a package essential for the overall operation of the system, YaST issues a warning. Such packages should be updated only in the update mode. For example, many packages contain shared libraries. Updating these programs and applications in the running system may lead to system instability.

12.2 More information Edit source

Problems and special issues of the various versions are published online as they are identified. See the links listed below. Important updates of individual packages can be accessed using the YaST Online Update. For more information, see Chapter 11, YaST online update.

Refer to the Product highlights (https://en.opensuse.org/Product_highlights and the Bugs article in the openSUSE wiki at https://en.opensuse.org/openSUSE:Most_annoying_bugs for information about recent changes and issues.

Part IV The Bash shell Edit source

13 Shell basics

When working with Linux, you can communicate with the system almost without ever requiring a command line interpreter (the shell). After booting your Linux system, you are usually directed to a graphical user interface that guides you through the login process and the following interactions with the…

14 Bash and Bash scripts

Today, many people use computers with a graphical user interface (GUI) like GNOME. Although GUIs offer many features, they are limited when performing automated task execution. Shells complement GUIs well, and this chapter gives an overview of several aspects of shells, in this case the Bash shell.

13 Shell basics Edit source

When working with Linux, you can communicate with the system almost without ever requiring a command line interpreter (the shell). After booting your Linux system, you are usually directed to a graphical user interface that guides you through the login process and the following interactions with the operating system. The graphical user interface in Linux is initially configured during installation and used by desktop environments such as KDE or GNOME.

Nevertheless, it is useful to have some basic knowledge of working with a shell because you might encounter situations where the graphical user interface is not available. For example, if some problem with the X Window System occurs. If you are not familiar with a shell, you might feel a bit uncomfortable at first when entering commands, but the more you get used to it, the more you will realize that the command line is often the quickest and easiest way to perform some daily tasks.

For Unix or Linux, several shells are available which differ slightly in behavior and in the commands they accept. The default shell in openSUSE® Leap is Bash (GNU Bourne-Again Shell).

The following sections will guide you through your first steps with the Bash shell and will show you how to complete some basic tasks via the command line. If you are interested in learning more or rather feel like a shell power user already, refer to Chapter 14, Bash and Bash scripts.

13.1 Starting a shell Edit source

Basically, there are two different ways to start a shell from the graphical user interface which usually shows after you have booted your computer:

  • you can leave the graphical user interface or

  • you can start a terminal window within the graphical user interface.

While the first option is always available, you can only make use of the second option when you are already logged in to a desktop such as KDE or GNOME. Whichever way you choose, there is always a way back and you can switch back and forth between the shell and the graphical user interface.

If you want to give it a try, press CtrlAltF2 to leave the graphical user interface. The graphical user interface disappears and you are taken to a shell which prompts you to log in. Type your username and press Enter. Then type your password and press Enter. The prompt now changes and shows some useful information as in the following example:

 1   2   3
tux@linux:~>

1

Your login.

2

The hostname of your computer.

3

Path to the current directory. Directly after login, the current directory usually is your home directory, indicated by the ~ symbol (tilde) .

When you are logged in at a remote computer the information provided by the prompt always shows you which system you are currently working on.

When the cursor is located behind this prompt, you can pass commands directly to your computer system. For example, you can now enter ls -l to list the contents of the current directory in a detailed format. If this is enough for your first encounter with the shell and you want to go back to the graphical user interface, you should log out from your shell session first. To do so, type exit and press Enter. Then press AltF7 to switch back to the graphical user interface. You will find your desktop and the applications running on it unchanged.

When you are already logged in to the GNOME or the KDE desktop and want to start a terminal window within the desktop, press AltF2 and enter konsole (for KDE) or gnome-terminal (for GNOME). This opens a terminal window on your desktop. As you are already logged in to your desktop, the prompt shows information about your system as described above. You can now enter commands and execute tasks just like in any shell which runs parallel to your desktop. To switch to another application on the desktop just click on the corresponding application window or select it from the taskbar of your panel. To close the terminal window press AltF4.

13.2 Entering commands Edit source

As soon as the prompt appears on the shell it is ready to receive and execute commands. A command can consist of several elements. The first element is the actual command, followed by parameters or options. You can type a command and edit it by using the following keys: , , Home, End, <— (Backspace), Del, and Space. You can correct typing errors or add options. The command is not executed until you press Enter.

Important
Important: No news is good news

The shell is not verbose: in contrast to some graphical user interfaces, it usually does not provide confirmation messages when commands have been executed. Messages only appear in case of problems or errors —or if you explicitly ask for them by executing a command with a certain option.

Also keep this in mind for commands to delete objects. Before entering a command like rm (without any option) for removing a file, you should know if you really want to get rid of the object: it will be deleted irretrievably, without confirmation.

13.2.1 Using commands without options Edit source

In Section 13.6.1, “Permissions for user, group and others” you already got to know one of the most basic commands: ls, which used to list the contents of a directory. This command can be used with or without options. Entering the plain ls command shows the contents of the current directory:

> ls
bin Desktop Documents public_html tux.txt
> 

Files in Linux may have a file extension or a suffix, such as .txt, but do not need to have one. This makes it difficult to differentiate between files and folders in this output of the ls. By default, the colors in the Bash shell give you a hint: directories are usually shown in blue, files in black.

13.2.2 Using commands with options Edit source

A better way to get more details about the contents of a directory is using the ls command with a string of options. Options modify the way a command works so that you can get it to carry out specific tasks. Options are separated from the command with a blank and are usually prefixed with a hyphen. The ls -l command shows the contents of the same directory in full detail (long listing format):

> ls -l
drwxr-xr-x 1 tux users     48 2015-06-23 16:08 bin
drwx---r-- 1 tux users  53279 2015-06-21 13:16 Desktop
drwx------ 1 tux users    280 2015-06-23 16:08 Documents
drwxr-xr-x 1 tux users  70733 2015-06-21 09:35 public_html
-rw-r--r-- 1 tux users  47896 2015-06-21 09:46 tux.txt
> 

This output shows the following information about each object:

drwxr-xr-x1 12 tux3 users4 485 2006-06-23 16:086 bin7

1

Type of object and access permissions. For further information, refer to Section 13.6.1, “Permissions for user, group and others”.

2

Number of hard links to this file.

3

Owner of the file or directory. For further information, refer to Section 13.6.1, “Permissions for user, group and others”.

4

Group assigned to the file or directory. For further information, refer to Section 13.6.1, “Permissions for user, group and others”.

5

File size in bytes.

6

Date and time of the last change.

7

Name of the object.

Usually, you can combine several options by prefixing only the first option with a hyphen and then write the others consecutively without a blank. For example, if you want to see all files in a directory in long listing format, you can combine the two options -l and -a (show all files) for the ls command. Executing ls -la shows also hidden files in the directory, indicated by a dot in front (for example, .hiddenfile).

The list of contents you get with ls is sorted alphabetically by filenames. But like in a graphical file manager, you can also sort the output of ls -l according to various criteria such as date, file extension or file size:

  • For date and time, use ls -lt (displays newest first).

  • For extensions, use ls -lx (displays files with no extension first).

  • For file size, use ls -lS (displays largest first).

To revert the order of sorting, add -r as an option to your ls command. For example, ls -lr gives you the contents list sorted in reverse alphabetical order, ls -ltr shows the oldest files first. There are lots of other useful options for ls. In the following section you will learn how to investigate them.

13.2.3 Bash shortcut keys Edit source

After having entered several commands, your shell will begin to fill up with all sorts of commands and the corresponding outputs. In the following table, find some useful shortcut keys for navigating and editing in the shell.

Shortcut Key

Function

CtrlL

Clears the screen and moves the current line to the top of the page.

CtrlC

Aborts the command which is currently being executed.

CtrlU

Deletes from cursor position to start of line.

CtrlK

Deletes from cursor position to the end of line.

CtrlD

Closes the shell session.

,

Browses in the history of executed commands.

13.3 Getting help Edit source

If you remember the name of command but are not sure about the options or the syntax of the command, choose one of the following possibilities:

--help/-h option

If you only want to look up the options of a certain command, try entering the command followed by a space and --help. This --help option exists for many commands. For example, ls --help displays all the options for the ls command.

Manual pages

To learn more about the various commands, you can also use the manual pages. Manual pages also give a short description of what the command does. They can be accessed with man followed by the name of the command, for example, man ls.

Man pages are displayed directly in the shell. To navigate them, use the following keys:

  • Move up and down with Page ↑ and Page ↓

  • Move between the beginning and the end of a document with Home and End

  • Quit the man page viewer by pressing Q

For more information about the man command, use man man.

Info pages

Info pages usually provide even more information about commands. To view the info page for a certain command, enter info followed by the name of the command (for example, info ls).

Info pages are displayed directly in the shell. To navigate them, use the following keys:

  • Use Space to move forward a section (node). Use <— to move backward a section.

  • Move up and down with Page ↑ and Page ↓

  • Quit the info page viewer by pressing Q

Note that man pages and info pages do not exist for all commands. Sometimes both are available (usually for key commands), sometimes only a man page or an info page exists, and sometimes neither of them are available.

13.4 Working with files and directories Edit source

To address a certain file or directory, you must specify the path leading to that directory or file. There are two ways to specify a path:

Absolute path

The entire path from the root directory (/) to the relevant file or directory. For example, the absolute path to a text file named file.txt in your Documents directory might be:

/home/tux/Documents/file.txt
Relative path

The path from the current working directory to the relevant file or directory. If your current working directory is /home/tux, the relative path file.txt in your Documents directory is:

Documents/file.txt

However, if your working directory is /home/tux/Music instead, you need to move up a level to /home/tux (with ..) before you can go further down:

../Documents/file.txt

Paths contain file names, directories or both, separated by slashes. Absolute paths always start with a slash. Relative paths do not have a slash at the beginning, but can have one or two dots.

When entering commands, you can choose either way to specify a path, depending on your preferences or the amount of typing, both will lead to the same result. To change directories, use the cd command and specify the path to the directory.

Note
Note: Handling blanks in filenames or directory names

If a filename or the name of a directory contains a space, either escape the space using a back slash (\) in front of the blank or enclose the filename in single quotes. Otherwise Bash interprets a filename like My Documents as the names of two files or directories, My and Documents in this case.

When specifying paths, the following shortcuts can save you a lot of typing:

  • The tilde symbol (~) is a shortcut for home directories. For example, to list the contents of your home directory, use ls ~. To list the contents of another user's home directory, enter ls ~USERNAME (or course, this will only work if you have permission to view the contents, see Section 13.6, “File access permissions”). For example, entering ls ~tux would list the contents of the home directory of a user named tux. You can use the tilde symbol as shortcut for home directories also if you are working in a network environment where your home directory may not be called /home but can be mapped to any directory in the file system.

    From anywhere in the file system, you can reach your home directory by entering cd ~ or by simply entering cd without any options.

  • When using relative paths, refer to the current directory with a dot (.). This is mainly useful for commands such as cp or mv by which you can copy or move files and directories.

  • The next higher level in the tree is represented by two dots (..). In order to switch to the parent directory of your current directory, enter cd .., to go up two levels from the current directory enter cd ../.. etc.

To apply your knowledge, find some examples below. They address basic tasks you may want to execute with files or folders using Bash.

13.4.1 Examples for working with files and directories Edit source

Suppose you want to copy a file located somewhere in your home directory to a subdirectory of /tmp that you need to create first.

Procedure 13.1: Creating and changing directories

From your home directory create a subdirectory in /tmp:

  1. Enter

    > mkdir /tmp/test

    mkdir stands for make directory. This command creates a new directory named test in the /tmp directory. In this case, you are using an absolute path to create the test directory.

  2. To check what happened, now enter

    > ls -l /tmp

    The new directory test should appear in the list of contents of the /tmp directory.

  3. Switch to the newly created directory with

    > cd /tmp/test
Procedure 13.2: Creating and copying files

Now create a new file in a subdirectory of your home directory and copy it to /tmp/test. Use a relative path for this task.

Important
Important: Overwriting of existing files

Before copying, moving or renaming a file, check if your target directory already contains a file with the same name. If yes, consider changing one of the filenames or use cp or mv with options like -i, which will prompt before overwriting an existing file. Otherwise Bash will overwrite the existing file without confirmation.

  1. To list the contents of your home directory, enter

    > ls -l ~

    It should contain a subdirectory called Documents by default. If not, create this subdirectory with the mkdir command you already know:

    > mkdir ~/Documents
  2. To create a new, empty file named myfile.txt in the Documents directory, enter

    > touch ~/Documents/myfile.txt

    Usually, the touch command updates the modification and access date for an existing file. If you use touch with a filename which does not exist in your target directory, it creates a new file.

  3. Enter

    > ls -l ~/Documents

    The new file should appear in the list of contents.

  4. To copy the newly created file, enter

    > cp ~/Documents/myfile.txt .

    Do not forget the dot at the end.

    This command tells Bash to go to your home directory and to copy myfile.txt from the Documents subdirectory to the current directory, /tmp/test, without changing the name of the file.

  5. Check the result by entering

    > ls -l

    The file myfile.txt should appear in the list of contents for /tmp/test.

Procedure 13.3: Renaming and removing files or directories

Now suppose you want to rename myfile.txt into tuxfile.txt. Finally you decide to remove the renamed file and the test subdirectory.

  1. To rename the file, enter

    > mv myfile.txt tuxfile.txt
  2. To check what happened, enter

    > ls -l

    Instead of myfile.txt, tuxfile.txt should appear in the list of contents.

    mv stands for move and is used with two options: the first option specifies the source, the second option specifies the target of the operation. You can use mv either

    • to rename a file or a directory,

    • to move a file or directory to a new location or

    • to do both in one step.

  3. Coming to the conclusion that you do not need the file any longer, you can delete it by entering

    > rm tuxfile.txt

    Bash deletes the file without any confirmation.

  4. Move up one level with cd .. and check with

    > ls -l test

    if the test directory is empty now.

  5. If yes, you can remove the test directory by entering

    > rmdir test

13.5 Becoming root Edit source

root, also called the superuser, has privileges which authorize them to access all parts of the system and to execute administrative tasks. They have the unrestricted capacity to make changes to the system and they have unlimited access to all files. Therefore, performing some administrative tasks or running certain programs such as YaST requires root permissions.

13.5.1 Using su Edit source

In order to temporarily become root in a shell, proceed as follows:

  1. Enter su. You are prompted for the root password.

  2. Enter the password. If you mistyped the root password, the shell displays a message. In this case, you have to re-enter su before retyping the password. If your password is correct, a hash symbol # appears at the end of the prompt, signaling that you are acting as root now.

  3. Execute your task. For example, transfer ownership of a file to a new user which only root is allowed to do:

    > chown wilber kde_quick.xml
  4. After having completed your tasks as root, switch back to your normal user account. To do so, enter

    > exit

    The hash symbol disappears and you are acting as normal user again.

13.5.2 Using sudo Edit source

Alternatively, you can also use sudo (superuser do) to execute some tasks which normally are for roots only. With sudo, administrators can grant certain users root privileges for some commands. Depending on the system configuration, users can then run root commands by entering their normal password only. Due to a timestamp function, users are only granted a ticket for a restricted period of time after having entered their password. The ticket usually expires after a few minutes. In openSUSE, sudo requires the root password by default (if not configured otherwise by your system administrator).

For users, sudo is convenient as it prevents you from switching accounts twice (to root and back again). To change the ownership of a file using sudo, only one command is necessary instead of three:

> sudo chown wilber kde_quick.xml

After you have entered the password which you are prompted for, the command is executed. If you enter a second root command shortly after that, you are not prompted for the password again, because your ticket is still valid. After a certain amount of time, the ticket automatically expires and the password is required again. This also prevents unauthorized persons from gaining root privileges in case a user forgets to switch back to their normal user account again and leaves a root shell open.

13.6 File access permissions Edit source

In Linux, objects such as files or folders or processes generally belong to the user who created or initiated them. There are some exceptions to this rule. For more information about the exceptions, refer to Book “Security and Hardening Guide”, Chapter 19 “Access control lists in Linux”. The group which is associated with a file or a folder depends on the primary group the user belongs to when creating the object.

When you create a new file or directory, initial access permissions for this object are set according to a predefined scheme. As an owner of a file or directory, you can change the access permissions for this object. For example, you can protect files holding sensitive data against read access by other users and you can authorize the members of your group or other users to write, read, or execute several of your files where appropriate. As root, you can also change the ownership of files or folders.

13.6.1 Permissions for user, group and others Edit source

Three permission sets are defined for each file object on a Linux system. These sets include the read, write, and execute permissions for each of three types of users—the owner, the group, and other users.

The following example shows the output of an ls -l command in a shell. This command lists the contents of a directory and shows the details for each file and folder in that directory.

Example 13.1: Access permissions for files and folders
-rw-r----- 1 tux users      0 2015-06-23 16:08 checklist.txt
-rw-r--r-- 1 tux users  53279 2015-06-21 13:16 gnome_quick.xml
-rw-rw---- 1 tux users      0 2015-06-23 16:08 index.htm
-rw-r--r-- 1 tux users  70733 2015-06-21 09:35 kde-start.xml
-rw-r--r-- 1 tux users  47896 2015-06-21 09:46 kde_quick.xml
drwxr-xr-x 2 tux users     48 2015-06-23 16:09 local
-rwxr--r-- 1 tux users 624398 2015-06-23 15:43 tux.sh

As shown in the third column, all objects belong to user tux. They are assigned to the group users which is the primary group the user tux belongs to. To retrieve the access permissions the first column of the list must be examined more closely. Let's have a look at the file kde-start.xml:

Type

User Permissions

Group Permissions

Permissions for Others

-

rw-

r--

r--

The first column of the list consists of one leading character followed by nine characters grouped in three blocks. The leading character indicates the file type of the object: in this case, the hyphen () shows that kde-start.xml is a file. If you find the character d instead, this shows that the object is a directory, like local in Example 13.1, “Access permissions for files and folders”.

The next three blocks show the access permissions for the owner, the group and other users (from left to right). Each block follows the same pattern: the first position shows read permissions (r), the next position shows write permissions (w), the last one shows execute permission (x). A lack of either permission is indicated by -. In our example, the owner of kde-start.xml has read and write access to the file but cannot execute it. The users group can read the file but cannot write or execute it. The same holds true for the other users as shown in the third block of characters.

13.6.2 Files and folders Edit source

Access permissions have a slightly different impact depending on the type of object they apply to: file or directory. The following table shows the details:

Table 13.1: Access permissions for files and directories

Access Permission

File

Folder

Read (r)

Users can open and read the file.

Users can view the contents of the directory. Without this permission, users cannot list the contents of this directory with ls -l, for example. However, if they only have execute permission for the directory, they can nevertheless access certain files in this directory if they know of their existence.

Write (w)

Users can change the file: They can add or drop data and can even delete the contents of the file. However, this does not include the permission to remove the file completely from the directory as long as they do not have write permissions for the directory where the file is located.

Users can create, rename or delete files in the directory.

Execute (x)

Users can execute the file. This permission is only relevant for files like programs or shell scripts, not for text files. If the operating system can execute the file directly, users do not need read permission to execute the file. However, if the file must me interpreted like a shell script or a perl program, additional read permission is needed.

Users can change into the directory and execute files there. If they do not have read access to that directory they cannot list the files but can access them nevertheless if they know of their existence.

Note that access to a certain file is always dependent on the correct combination of access permissions for the file itself and the directory it is located in.

13.6.3 Modifying file permissions Edit source

In Linux, objects such as files or folder or processes generally belong to the user who created or initiated them. The group which is associated with a file or a folder depends on the primary group the user belongs to when creating the object. When you create a new file or directory, initial access permissions for this object are set according to a predefined scheme. For further details refer to Section 13.6, “File access permissions”.

As the owner of a file or directory (and, of course, as root), you can change the access permissions to this object.

To change object attributes like access permissions of a file or folder, use the chmod command followed by the following parameters:

  • the users for which to change the permissions,

  • the type of access permission you want to remove, set or add and

  • the files or folders for which you want to change permissions separated by spaces.

The users for which you can change file access permissions fall into the following categories: the owner of the file (user, u), the group that own the file (group, g) and the other users (others, o). You can add, remove or set one or more of the following permissions: read, write or execute.

As root, you can also change the ownership of a file: with the command chown (change owner) you can transfer ownership to a new user.

13.6.3.1 Examples for changing access permissions and ownership Edit source

The following example shows the output of an ls -l command in a shell.

Example 13.2: Access permissions for files and folders
-rw-r----- 1 tux users      0 2015-06-23 16:08 checklist.txt
-rw-r--r-- 1 tux users  53279 2015-06-21 13:16 gnome_quick.xml
-rw-rw---- 1 tux users      0 2015-06-23 16:08 index.htm
-rw-r--r-- 1 tux users  70733 2015-06-21 09:35 kde-start.xml
-rw-r--r-- 1 tux users  47896 2015-06-21 09:46 kde_quick.xml
drwxr-xr-x 2 tux users     48 2015-06-23 16:09 local
-r-xr-xr-x 1 tux users 624398 2015-06-23 15:43 tux.jpg

In the example above, user tux owns the file kde-start.xml and has read and write access to the file but cannot execute it. The users group can read the file but cannot write or execute it. The same holds true for the other users as shown by the third block of characters.

Procedure 13.4: Changing access permissions

Suppose you are tux and want to modify the access permissions to your files:

  1. If you want to grant the users group also write access to kde-start.xml, enter

    > chmod g+w kde-start.xml
  2. To grant the users group and other users write access to kde-start.xml, enter

    > chmod go+w kde-start.xml
  3. To remove write access for all users, enter

    > chmod -w kde-start.xml

    If you do not specify any kind of users, the changes apply to all users— the owner of the file, the owning group and the others. Now even the owner tux does not have write access to the file without first reestablishing write permissions.

  4. To prohibit the users group and others to change into the directory local, enter

    > chmod go-x local
  5. To grant others write permissions for two files, for kde_quick.xml and gnome_quick.xml, enter

    > chmod o+w  kde_quick.xml gnome_quick.xml
Procedure 13.5: Changing ownership

Suppose you are tux and want to transfer the ownership of the file kde_quick.xml to an other user, named wilber. In this case, proceed as follows:

  1. Enter the username and password for root.

  2. Enter

    # chown wilber kde_quick.xml
  3. Check what happened with

    > ls -l kde_quick.xml

    You should get the following output:

    -rw-r--r-- 1 wilber users  47896 2006-06-21 09:46 kde_quick.xml
  4. If the ownership is set according to your wishes, switch back to your normal user account.

13.7 Time-saving features of Bash Edit source

Entering commands in Bash can involve a lot of typing. This section introduces some features that can save you both time and typing.

History

By default, Bash remembers commands you have entered. This feature is called history. You can browse through commands that have been entered before, select one you want to repeat and then execute it again. To do so, press repeatedly until the desired command appears at the prompt. To move forward through the list of previously entered commands, press . For easier repetition of a certain command from Bash history, just type the first letter of the command you want to repeat and press Page ↑.

You can now edit the selected command (for example, change the name of a file or a path), before you execute the command by pressing Enter. To edit the command line, move the cursor to the desired position using the arrow keys and start typing.

You can also search for a certain command in the history. Press CtrlR to start an incremental search function. showing the following prompt:

> (reverse-i-search)`':

Just type one or several letters from the command you are searching for. Each character you enter narrows down the search. The corresponding search result is shown on the right side of the colon whereas your input appears on the left of the colon. To accept a search result, press Esc. The prompt now changes to its normal appearance and shows the command you chose. You can now edit the command or directly execute it by pressing Enter.

Completion

Completing a filename or directory name to its full length after typing its first letters is another helpful feature of Bash. To do so, type the first letters then press →| (Tabulator). If the filename or path can be uniquely identified, it is completed at once and the cursor moves to the end of the filename. You can then enter the next option of the command, if necessary. If the filename or path cannot be uniquely identified (because there are several filenames starting with the same letters), the filename or path is only completed up to the point where it becomes ambiguous again. You can then obtain a list of them by pressing →| a second time. After this, you can enter the next letters of the file or path then try completion again by pressing →|. When completing filenames and paths with →|, you can simultaneously check whether the file or path you want to enter really exists (and you can be sure of getting the spelling right).

Wild cards

You can replace one or more characters in a filename with a wild card for pathname expansion. Wild cards are characters that can stand for other characters. There are three different types of these in Bash:

Wild Card

Function

?

Matches exactly one arbitrary character

*

Matches any number of characters

[SET]

Matches one of the characters from the group specified inside the square brackets, which is represented here by the string SET.

13.7.1 Examples for using history, completion and wild cards Edit source

The following examples illustrate how to make use of these convenient features of Bash.

Procedure 13.6: Using history and completion

If you already did the example Section 13.4.1, “Examples for working with files and directories”, your shell buffer should be filled with commands which you can retrieve using the history function.

  1. Press repeatedly until cd ~ appears.

  2. Press Enter to execute the command and to switch to your home directory.

    By default, your home directory contains two subdirectories starting with the same letter, Documents and Desktop.

  3. Type cd D and press →|.

    Nothing happens since Bash cannot identify to which one of the subdirectories you want to change.

  4. Press →| again to see the list of possible choices:

    > cd D
    Desktop/ Documents/ Downloads/
    > cd D
  5. The prompt still shows your initial input. Type the next character of the subdirectory you want to go to and press →| again.

    Bash now completes the path.

  6. You can now execute the command with Enter.

Procedure 13.7: Using wild cards

Now suppose that your home directory contains several files with various file extensions. It also holds several versions of one file which you saved under different filenames myfile1.txt, myfile2.txt etc. You want to search for certain files according to their properties.

  1. First, create some test files in your home directory:

    1. Use the touch command to create several (empty) files with different file extensions, for example .pdf, .xml and .jpg.

      You can do this consecutively (do not forget to use the Bash history function) or with only one touch command: simply add several filenames separated by a space.

    2. Create at least two files that have the same file extension, for example .html.

    3. To create several versions of one file, enter

      > touch myfile{1..5}.txt

      This command creates five consecutively numbered files: myfile1.txt, …, myfile5.txt.

    4. List the contents of the directory. It should look similar to this:

      > ls -l
      -rw-r--r-- 1 tux users   0 2006-07-14 13:34 foo.xml
      -rw-r--r-- 1 tux users   0 2006-07-14 13:47 home.html
      -rw-r--r-- 1 tux users   0 2006-07-14 13:47 index.html
      -rw-r--r-- 1 tux users   0 2006-07-14 13:47 toc.html
      -rw-r--r-- 1 tux users   0 2006-07-14 13:34 manual.pdf
      -rw-r--r-- 1 tux users   0 2006-07-14 13:49 myfile1.txt
      -rw-r--r-- 1 tux users   0 2006-07-14 13:49 myfile2.txt
      -rw-r--r-- 1 tux users   0 2006-07-14 13:49 myfile3.txt
      -rw-r--r-- 1 tux users   0 2006-07-14 13:49 myfile4.txt
      -rw-r--r-- 1 tux users   0 2006-07-14 13:49 myfile5.txt
      -rw-r--r-- 1 tux users   0 2006-07-14 13:32 tux.png
  2. With wild cards, select certain subsets of the files according to various criteria:

    1. To list all files with the .html extension, enter

      > ls -l *.html
    2. To list all versions of myfile.txt, enter

      > ls -l myfile?.txt

      Note that you can only use the ? wild card here because the numbering of the files is single-digit. As soon as you have a file named myfile10.txt you must to use the * wild card to view all versions of myfile.txt (or add another question mark, so your string looks like myfile??.txt).

    3. To remove, for example, version 1-3 and version 5 of myfile.txt, enter

      > rm myfile[1-3,5].txt
    4. Check the result with

      > ls -l

      Of all myfile.txt versions only myfile4.txt should be left.

You can also combine several wild cards in one command. In the example above, rm myfile[1-3,5].* would lead to the same result as rm myfile[1-3,5].txt because there are only files with the extension .txt available.

Note
Note: Using wild cards in rm commands

Wild cards in a rm command can be very useful but also dangerous: you might delete more files from your directory than intended. To see which files would be affected by the rm, run your wild card string with ls instead of rm first.

13.8 Editing texts Edit source

In order to edit files from the command line, you will need to know the vi editor. vi is a default editor which can be found on nearly every UNIX/Linux system. It can run several operating modes in which the keys you press have different functions. This does not make it very easy for beginners, but you should know at least the most basic operations with vi. There may be situations where no other editor than vi is available.

Basically, vi makes use of three operating modes:

command mode

In this mode, vi accepts certain key combinations as commands. Simple tasks such as searching words or deleting a line can be executed.

insert mode

In this mode, you can write normal text.

extended mode

In this mode, also known as colon mode (as you have to enter a colon to switch to this mode), vi can execute also more complex tasks such as searching and replacing text.

In the following (very simple) example, you will learn how to open and edit a file with vi, how to save your changes and quit vi.

13.8.1 Example: editing with vi Edit source

Note
Note: Display of keys

In the following, find several commands that you can enter in vi by just pressing keys. These appear in uppercase as on a keyboard. If you need to enter a key in uppercase, this is stated explicitly by showing a key combination including the Shift key.

  1. To create and open a new file with vi, enter

    > vi textfile.txt

    By default, vi opens in command mode in which you cannot enter text.

  2. Press I to switch to insert mode. The bottom line changes and indicates that you now can insert text.

  3. Write some sentences. If you want to insert a new line, first press Esc to switch back to command mode. Press O to insert a new line and to switch to insert mode again.

  4. In the insert mode, you can edit the text with the arrow keys and with Del.

  5. To leave vi, press Esc to switch to command mode again. Then press : which takes you to the extended mode. The bottom line now shows a colon.

  6. To leave vi and save your changes, type wq (w for write; q for quit) and press Enter. If you want to save the file under a different name, type w FILENAME and press Enter.

    To leave vi without saving, type q! instead and press Enter.

13.10 Viewing text files Edit source

When searching for the contents of a file with grep, the output gives you the line in which the searchstring was found along with the filename. Often this contextual information is still not enough information to decide whether you want to open and edit this file. Bash offers you several commands to have a quick look at the contents of a text file directly in the shell, without opening an editor.

head

With head you can view the first lines of a text file. If you do not specify the command any further, head shows the first 10 lines of a text file.

tail

The tail command is the counterpart of head. If you use tail without any further options it displays the last 10 lines of a text file. This can be very useful to view log files of your system, where the most recent messages or log entries are usually found at the end of the file.

less

With less, display the whole contents of a text file. To move up and down half a page use Page ↑ and Page ↓. Use Space to scroll down one page. Home takes you to the beginning, and End to the end of the document. To end the viewing mode, press Q.

more

Instead of less, you can also use the older program more. It has basically the same function—however, it is less convenient because it does not allow you to scroll backward. Use Space to move forward. When you reach the end of the document, the viewer closes automatically.

cat

The cat command displays the contents of a file, printing the entire contents to the screen without interruption. As cat does not allow you to scroll it is not very useful as viewer but it is rather often used in combination with other commands.

13.11 Redirection and pipes Edit source

Sometimes it would be useful if you could write the output of a command to a file for further editing or if you could combine several commands, using the output of one command as the input for the next one. The shell offers this function by means of redirection or pipes.

Normally, the standard output in the shell is your screen (or an open shell window) and the standard input is the keyboard. With certain symbols you can redirect the input or the output to another object, such as a file or another command.

Redirection

With > you can forward the output of a command to a file (output redirection), with < you can use a file as input for a command (input redirection).

Pipe

By means of a pipe symbol | you can also redirect the output: with a pipe, you can combine several commands, using the output of one command as input for the next command. In contrast to the other redirection symbols > and <, the use of the pipe is not constrained to files.

13.11.1 Examples for redirection and pipe Edit source

  1. To write the output of a command like ls to a file, enter

    > ls -l > filelist.txt

    This creates a file named filelist.txt that contains the list of contents of your current directory as generated by the ls command.

    However, if a file named filelist.txt already exists, this command overwrites the existing file. To prevent this, use >> instead of >. Entering

    > ls -l >> filelist.txt

    simply appends the output of the ls command to an already existing file named filelist.txt. If the file does not exist, it is created.

  2. Redirections also works the other way round. Instead of using the standard input from the keyboard for a command, you can use a file as input:

    > sort < filelist.txt

    This will force the sort command to get its input from the contents of filelist.txt. The result is shown on the screen. Of course, you can also write the result into another file, using a combination of redirections:

    > sort < filelist.txt > sorted_filelist.txt
  3. If a command generates a lengthy output, like ls -l may do, it may be useful to pipe the output to a viewer like less to be able to scroll through the pages. To do so, enter

    > ls -l | less

    The list of contents of the current directory is shown in less.

    The pipe is also often used in combination with the grep command in order to search for a certain string in the output of another command. For example, if you want to view a list of files in a directory which are owned by the user tux, enter

    > ls -l | grep tux

13.12 Starting programs and handling processes Edit source

As you have seen in Section 13.8, “Editing texts”, programs can be started from the shell. Applications with a graphical user interface need the X Window System and can only be started from a terminal window within a graphical user interface. For example, if you want to open a file named vacation.pdf in your home directory from a terminal window in KDE or GNOME, simply run okular ~/vacation.pdf (or evince ~/vacation.pdf) to start a PDF viewer displaying your file.

When looking at the terminal window again you will realize that the command line is blocked as long as the PDF viewer is open, meaning that your prompt is not available. To change this, press CtrlZ to suspend the process and enter bg to send the process to the background.

Now you can still have a look at vacation.pdf while your prompt is available for further commands. An easier way to achieve this is by sending a process to the background directly when starting it. To do so, add an ampersand at the end of the command:

> okular ~/vacation.pdf &

If you have started several background processes (also named jobs) from the same shell, the jobs command gives you an overview of the jobs. It also shows the job number in brackets and their status:

> jobs
[1]   Running        okular book.opensuse.startup-xep.pdf &
[2]-  Running        okular book.opensuse.reference-xep.pdf &
[3]+  Stopped        man jobs

To bring a job to the foreground again, enter fg JOB_NUMBER.

Whereas job only shows the background processes started from a specific shell, the ps command (run without options) shows a list of all your processes—those you started. Find an example output below:

> ps
PID TTY          TIME CMD
15500 pts/1    00:00:00 bash
28214 pts/1    00:00:00 okular
30187 pts/1    00:00:00 kwrite
30280 pts/1    00:00:00 ps

In case a program cannot be terminated in the normal way, use the kill command to stop the process (or processes) belonging to that program. To do so, specify the process ID (PID) shown by the output of ps. For example, to shut down the KWrite editor in the example above, enter

> kill 30187

This sends a TERM signal that instructs the program to shut itself down.

Alternatively, if the program or process you want to terminate is a background job and is shown by the jobs command, you can also use the kill command in combination with the job number to terminate this process. When identifying the job with the job number, you must prefix the number with a percent character (%):

> kill %JOB_NUMBER

If kill does not help—as is sometimes the case for runaway programs—try

> kill -9 PID

This sends a KILL signal instead of a TERM signal, usually bringing the specified process to an end.

This section is intended to introduce the most basic set of commands for handling jobs and processes. Find an overview for system administrators in Book “System Analysis and Tuning Guide”, Chapter 2 “System monitoring utilities”, Section 2.3 “Processes”.

13.13 Archives and data compression Edit source

On Linux, there are two types of commands that make data easier to transfer:

  • Archivers, which create a big file out of several smaller ones. The most commonly used archiver is tar, another example is cpio.

  • Compressors, which losslessly make a file smaller. The most commonly used compressors are gzip and bzip2.

When combining these two types of commands, their effect is comparable to the compressed archive files that are prevalent on other operating systems, for example, ZIP or RAR.

To pack the test directory with all its files and subdirectories into an archive named testarchive.tar, do the following:

Procedure 13.8: Archiving files
  1. Open a shell.

  2. Use cd to change to your home directory where the test directory is located.

  3. Compress the file with:

    > tar -cvf testarchive.tar test

    The -c option creates the archive, making it a file as directed by -f. The -v option lists the files as they are processed.

    The test directory with all its files and directories has remained unchanged on your hard disk.

  4. View the contents of the archive file with:

    > tar -tf testarchive.tar
  5. To unpack the archive, use:

    > tar -xvf testarchive.tar

    If files in your current directory are named the same as the files in the archive, they will be overwritten without warning.

To compress files, use gzip or, for better compression, bzip2.

Procedure 13.9: Compressing a file
  1. For this example, reuse the archive testarchive.tar from Procedure 13.8, “Archiving files”.

    To compress the archive, use:

    > gzip testarchive.tar

    With ls, now see that the file testarchive.tar is no longer there and that the file testarchive.tar.gz has been created instead.

    As an alternative, use bzip2 testarchive.tar which works analogously but provides somewhat better compression.

  2. Now decompress and unarchive the file again:

    • This can be done in two steps by first decompressing and then unarchiving the file:

      > gzip --decompress testarchive.tar.gz
      > tar -xvf testarchive.tar
    • You can also decompress and unarchive in one step:

      > tar -xvf testarchive.tar

    With ls, you can see that a new test directory has been created with the same contents as your test directory in your home directory.

13.14 Important Linux commands Edit source

This section provides an overview of the most important Linux commands. There are many more commands than listed in this chapter. Along with the individual commands, parameters are listed and, where appropriate, a typical sample application is introduced.

Adjust the parameters to your needs. It makes no sense to write ls file if no file named file actually exists. You can usually combine several parameters, for example, by writing ls -la instead of ls -l -a.

13.14.1 File commands Edit source

The following section lists the most important commands for file management. It covers everything from general file administration to the manipulation of file system ACLs.

13.14.1.1 File administration Edit source

ls OPTIONS FILES

If you run ls without any additional parameters, the program lists the contents of the current directory in short form.

-l

Detailed list

-a

Displays hidden files

cp OPTIONS SOURCE TARGET

Copies source to target.

-i

Waits for confirmation, if necessary, before an existing target is overwritten

-r

Copies recursively (includes subdirectories)

mv OPTIONS SOURCE TARGET

Copies source to target then deletes the original source.

-b

Creates a backup copy of the source before moving

-i

Waits for confirmation, if necessary, before an existing targetfile is overwritten

rm OPTIONS FILES

Removes the specified files from the file system. Directories are not removed by rm unless the option -r is used.

-r

Deletes any existing subdirectories

-i

Waits for confirmation before deleting each file

ln OPTIONS SOURCE TARGET

Creates an internal link from source to target. Normally, such a link points directly to source on the same file system. However, if ln is executed with the -s option, it creates a symbolic link that only points to the directory in which source is located, enabling linking across file systems.

-s

Creates a symbolic link

cd OPTIONS DIRECTORY

Changes the current directory. cd without any parameters changes to the user's home directory.

mkdir OPTIONS DIRECTORY

Creates a new directory.

rmdir OPTIONS DIRECTORY

Deletes the specified directory if it is already empty.

chown OPTIONS USER_NAME[:GROUP] FILES

Transfers ownership of a file to the user with the specified user name.

-R

Changes files and directories in all subdirectories

chgrp OPTIONS GROUP_NAME FILES

Transfers the group ownership of a given file to the group with the specified group name. The file owner can change group ownership only if a member of both the current and the new group.

chmod OPTIONS MODE FILES

Changes the access permissions.

The mode parameter has three parts: group, access, and access type. group accepts the following characters:

u

User

g

Group

o

Others

For access, grant access with + and deny it with -.

The access type is controlled by the following options:

r

Read

w

Write

x

Execute—executing files or changing to the directory

s

Setuid bit—the application or program is started as if it were started by the owner of the file

As an alternative, a numeric code can be used. The four digits of this code are composed of the sum of the values 4, 2, and 1—the decimal result of a binary mask. The first digit sets the set user ID (SUID) (4), the set group ID (2), and the sticky (1) bits. The second digit defines the permissions of the owner of the file. The third digit defines the permissions of the group members and the last digit sets the permissions for all other users. The read permission is set with 4, the write permission with 2, and the permission for executing a file is set with 1. The owner of a file would usually receive a 6 or a 7 for executable files.

gzip PARAMETERS FILES

This program compresses the contents of files using complex mathematical algorithms. Files compressed in this way are given the extension .gz and need to be uncompressed before they can be used. To compress several files or even entire directories, use the tar command.

-d

Decompresses the packed gzip files so they return to their original size and can be processed normally (like the command gunzip)

tar OPTIONS ARCHIVE FILES

tar puts one or more files into an archive. Compression is optional. tar is a quite complex command with several options available. The most frequently used options are:

-f

Writes the output to a file and not to the screen as is usually the case

-c

Creates a new TAR archive

-r

Adds files to an existing archive

-t

Outputs the contents of an archive

-u

Adds files, but only if they are newer than the files already contained in the archive

-x

Unpacks files from an archive (extraction)

-z

Packs the resulting archive with gzip

-j

Compresses the resulting archive with bzip2

-v

Lists files processed

The archive files created by tar end with .tar. If the TAR archive was also compressed using gzip, the ending is .tgz or .tar.gz. If it was compressed using bzip2, the ending is .tar.bz2.

find OPTIONS

With find, search for a file in a given directory. The first argument specifies the directory in which to start the search. The option -name must be followed by a search string, which may also include wild cards. Unlike locate, which uses a database, find scans the actual directory.

13.14.1.2 Commands to access file contents Edit source

file OPTIONS FILES

In Linux, files can have a file extensions but do not need to have one. The file determines the file type of a given file. With the output of file, you can then choose an appropriate application with which to open the file.

-z

Tries to look inside compressed files

cat OPTIONS FILES

The cat command displays the contents of a file, printing the entire contents to the screen without interruption.

-n

Numbers the output on the left margin

less OPTIONS FILES

This command can be used to browse the contents of the specified file. Scroll half a screen page up or down with Page ↑ and Page ↓ or a full screen page down with Space. Jump to the beginning or end of a file using Home and End. Press Q to quit the program.

grep OPTIONS SEARCH_STRING FILES

The grep command finds a specific search string in the specified files. If the search string is found, the command displays the line in which SEARCH_STRING was found along with the file name.

-i

Ignores case

-H

Only displays the names of the relevant files, but not the text lines

-n

Additionally displays the numbers of the lines in which it found a hit

-l

Only lists the files in which searchstring does not occur

diff OPTIONS FILE_1 FILE_2

The diff command compares the contents of any two files. The output produced by the program lists all lines that do not match. This is frequently used by programmers who need only to send their program alterations and not the entire source code.

-q

Only reports whether the two files differ

-u

Produces a unified diff, which makes the output more readable

13.14.1.3 File systems Edit source

mount OPTIONS DEVICE MOUNT_POINT

This command can be used to mount any data media, such as hard disks, CD-ROM drives, and other drives, to a directory of the Linux file system.

-r

Mount read-only

-t FILE_SYSTEM

Specify the file system: For Linux hard disks, this is commonly ext4, xfs, or btrfs.

For hard disks not defined in the file /etc/fstab, the device type must also be specified. In this case, only root can mount it. If the file system needs to also be mounted by other users, enter the option user in the appropriate line in the /etc/fstab file (separated by commas) and save this change. Further information is available in the mount(1) man page.

umount OPTIONS MOUNT_POINT

This command unmounts a mounted drive from the file system. To prevent data loss, run this command before taking a removable data medium from its drive. Normally, only root is allowed to run the commands mount and umount. To enable other users to run these commands, edit the /etc/fstab file to specify the option user for the relevant drive.

13.14.2 System commands Edit source

The following section lists a few of the most important commands needed for retrieving system information and controlling processes and the network.

13.14.2.1 System information Edit source

df OPTIONS DIRECTORY

The df (disk free) command, when used without any options, displays information about the total disk space, the disk space currently in use, and the free space on all the mounted drives. If a directory is specified, the information is limited to the drive on which that directory is located.

-h

Shows the number of occupied blocks in gigabytes, megabytes, or kilobytes—in human-readable format

-T

Type of file system (ext2, nfs, etc.)

du OPTIONS PATH

This command, when executed without any parameters, shows the total disk space occupied by files and subdirectories in the current directory.

-a

Displays the size of each individual file

-h

Output in human-readable form

-s

Displays only the calculated total size

free OPTIONS

The command free displays information about RAM and swap space usage, showing the total and the used amount in both categories. See Book “Reference”, Chapter 15 “Special system features”, Section 15.1.7 “The free command” for more information.

-b

Output in bytes

-k

Output in kilobytes

-m

Output in megabytes

date OPTIONS

This simple program displays the current system time. If run as root, it can also be used to change the system time. Details about the program are available in the date(1) man page.

13.14.2.2 Processes Edit source

top OPTIONS

top provides a quick overview of the currently running processes. Press H to access a page that briefly explains the main options for customizing the program.

ps OPTIONS PROCESS_ID

If run without any options, this command displays a table of all your own programs or processes—those you started. The options for this command are not preceded by hyphen.

aux

Displays a detailed list of all processes, independent of the owner

kill OPTIONS PROCESS_ID

Unfortunately, sometimes a program cannot be terminated in the normal way. In most cases, you should still be able to stop such a runaway program by executing the kill command, specifying the respective process ID (see top and ps). kill sends a TERM signal that instructs the program to shut itself down. If this does not help, the following parameter can be used:

-9

Sends a KILL signal instead of a TERM signal, bringing the specified process to an end in almost all cases

killall OPTIONS PROCESS_NAME

This command is similar to kill, but uses the process name (instead of the process ID) as an argument, ending all processes with that name.

13.14.2.3 Network Edit source

ping OPTIONS HOSTNAME_OR_IP_ADDRESS

The ping command is the standard tool for testing the basic functionality of TCP/IP networks. It sends a small data packet to the destination host, requesting an immediate reply. If this works, ping displays a message to that effect, which indicates that the network link is functioning.

-cNUMBER

Determines the total number of packages to send and ends after they have been dispatched (by default, there is no limitation set)

-f

flood ping: sends as many data packages as possible; a popular means, reserved for root, to test networks

-iVALUE

Specifies the interval between two data packages in seconds (default: one second)

host OPTIONS HOSTNAME SERVER

The domain name system resolves domain names to IP addresses. With this tool, send queries to name servers (DNS servers).

ssh OPTIONS [USER@]HOSTNAME COMMAND

SSH is actually an Internet protocol that enables you to work on remote hosts across a network. SSH is also the name of a Linux program that uses this protocol to enable operations on remote computers.

13.14.2.4 Miscellaneous Edit source

passwd OPTIONS USER_NAME

Users may change their own passwords at any time using this command. The administrator root can use the command to change the password of any user on the system.

su OPTIONS USER_NAME

The su command makes it possible to log in under a different user name from a running session. Specify a user name and the corresponding password. The password is not required from root, because root is authorized to assume the identity of any user. When using the command without specifying a user name, you are prompted for the root password and change to the superuser (root). Use su - to start a login shell for a different user.

halt OPTIONS

To avoid loss of data, you should always use this program to shut down your system.

reboot OPTIONS

Does the same as halt except the system performs an immediate reboot.

clear

This command cleans up the visible area of the console. It has no options.

13.14.3 More information Edit source

There are many more commands than listed in this chapter. For information about other commands or more detailed information, also see the publication Linux in a Nutshell by O'Reilly.

14 Bash and Bash scripts Edit source

Abstract

Today, many people use computers with a graphical user interface (GUI) like GNOME. Although GUIs offer many features, they are limited when performing automated task execution. Shells complement GUIs well, and this chapter gives an overview of several aspects of shells, in this case the Bash shell.

14.1 What is the shell? Edit source

Traditionally, the Linux shell is Bash (Bourne again Shell). When this chapter speaks about the shell it means Bash. There are more shells available (ash, csh, ksh, zsh, …), each employing different features and characteristics. If you need further information about other shells, search for shell in YaST.

14.1.1 Bash configuration files Edit source

A shell can be invoked as an:

  1. Interactive login shell.  This is used when logging in to a machine, invoking Bash with the --login option or when logging in to a remote machine with SSH.

  2. Ordinary interactive shell.  This is normally the case when starting xterm, konsole, gnome-terminal, or similar command line interface (CLI) tools.

  3. Non-interactive shell.  This is invoked when invoking a shell script at the command line.

Each shell reads different configuration files. The following tables show the login and non-login shell configuration files.

Tip
Tip

Bash looks for its configuration files in a specific order depending on the type of shell where it is run. Find more details on the Bash man page (man 1 bash). Search for the headline INVOCATION.

Table 14.1: Bash configuration files for login shells

File

Description

/etc/profile

Do not modify this file, otherwise your modifications may be destroyed during your next update.

/etc/profile.local

Use this file if you extend /etc/profile

/etc/profile.d/

Contains system-wide configuration files for specific programs

~/.profile

Insert user specific configuration for login shells here

The login shell also sources the configuration files listed under Table 14.2, “Bash configuration files for non-login shells”.

Table 14.2: Bash configuration files for non-login shells

/etc/bash.bashrc

Do not modify this file, otherwise your modifications may be destroyed during your next update.

/etc/bash.bashrc.local

Use this file to insert your system-wide modifications for Bash only

~/.bashrc

Insert user specific configuration here

Additionally, Bash uses multiple files:

Table 14.3: Special files for Bash

File

Description

~/.bash_history

Contains a list of all commands you have typed

~/.bash_logout

Executed when logging out

~/.alias

User defined aliases of frequently used commands. See man 1 alias for more details about defining aliases.

No-Login ShellsEdit source

There are special shells that block users from logging into the system: /bin/false and /sbin/nologin. Both fail silently when the user attempts to log into the system. This was intended as a security measure for system users, though modern Linux operating systems have more effective tools for controlling system access, such as PAM and AppArmor.

The default on openSUSE Leap is to assign /bin/bash to human users, and /bin/false or /sbin/nologin to system users. The nobody user has /bin/bash for historical reasons, as it is a user with minimum privileges that used to be the default for system users. However, whatever little bit of security gained by using nobody is lost when multiple system users use it. It should be possible to change it to /sbin/nologin; the fastest way to test it is change it and see if it breaks any services or applications.

Use the following command to list which shells are assigned to all users, system and human users, in /etc/passwd. The output varies according to the services and users on your system:

> sort -t: -k 7 /etc/passwd | awk -F: '{print $1"\t" $7}' | column -t
tux               /bin/bash
nobody            /bin/bash
root              /bin/bash
avahi             /bin/false
chrony            /bin/false
dhcpd             /bin/false
dnsmasq           /bin/false
ftpsecure         /bin/false
lightdm           /bin/false
mysql             /bin/false
postfix           /bin/false
rtkit             /bin/false
sshd              /bin/false
tftp              /bin/false
unbound           /bin/false
bin               /sbin/nologin
daemon            /sbin/nologin
ftp               /sbin/nologin
lp                /sbin/nologin
mail              /sbin/nologin
man               /sbin/nologin
nscd              /sbin/nologin
polkitd           /sbin/nologin
pulse             /sbin/nologin
qemu              /sbin/nologin
radvd             /sbin/nologin
rpc               /sbin/nologin
statd             /sbin/nologin
svn               /sbin/nologin
systemd-coredump  /sbin/nologin
systemd-network   /sbin/nologin
systemd-timesync  /sbin/nologin
usbmux            /sbin/nologin
vnc               /sbin/nologin
wwwrun            /sbin/nologin
messagebus        /usr/bin/false
scard             /usr/sbin/nologin

14.1.2 The directory structure Edit source

The following table provides a short overview of the most important higher-level directories that you find on a Linux system. Find more detailed information about the directories and important subdirectories in the following list.

Table 14.4: Overview of a standard directory tree

Directory

Contents

/

Root directory—the starting point of the directory tree.

/bin

Essential binary files, such as commands that are needed by both the system administrator and normal users. Usually also contains the shells, such as Bash.

/boot

Static files of the boot loader.

/dev

Files needed to access host-specific devices.

/etc

Host-specific system configuration files.

/home

Holds the home directories of all users who have accounts on the system. However, root's home directory is not located in /home but in /root.

/lib

Essential shared libraries and kernel modules.

/media

Mount points for removable media.

/mnt

Mount point for temporarily mounting a file system.

/opt

Add-on application software packages.

/root

Home directory for the superuser root.

/sbin

Essential system binaries.

/srv

Data for services provided by the system.

/tmp

Temporary files.

/usr

Secondary hierarchy with read-only data.

/var

Variable data such as log files.

/windows

Only available if you have both Microsoft Windows* and Linux installed on your system. Contains the Windows data.

The following list provides more detailed information and gives some examples of which files and subdirectories can be found in the directories:

/bin

Contains the basic shell commands that may be used both by root and by other users. These commands include ls, mkdir, cp, mv, rm and rmdir. /bin also contains Bash, the default shell in openSUSE Leap.

/boot

Contains data required for booting, such as the boot loader, the kernel, and other data that is used before the kernel begins executing user-mode programs.

/dev

Holds device files that represent hardware components.

/etc

Contains local configuration files that control the operation of programs like the X Window System. The /etc/init.d subdirectory contains LSB init scripts that can be executed during the boot process.

/home/USERNAME

Holds the private data of every user who has an account on the system. The files located here can only be modified by their owner or by the system administrator. By default, your e-mail directory and personal desktop configuration are located here in the form of hidden files and directories, such as .gconf/ and .config.

Note
Note: Home directory in a network environment

If you are working in a network environment, your home directory may be mapped to a directory in the file system other than /home.

/lib

Contains the essential shared libraries needed to boot the system and to run the commands in the root file system. The Windows equivalent for shared libraries are DLL files.

/media

Contains mount points for removable media, such as CD-ROMs, flash disks, and digital cameras (if they use USB). /media generally holds any type of drive except the hard disk of your system. When your removable medium has been inserted or connected to the system and has been mounted, you can access it from here.

/mnt

This directory provides a mount point for a temporarily mounted file system. root may mount file systems here.

/opt

Reserved for the installation of third-party software. Optional software and larger add-on program packages can be found here.

/root

Home directory for the root user. The personal data of root is located here.

/run

A tmpfs directory used by systemd and various components. /var/run is a symbolic link to /run.

/sbin

As the s indicates, this directory holds utilities for the superuser. /sbin contains the binaries essential for booting, restoring and recovering the system in addition to the binaries in /bin.

/srv

Holds data for services provided by the system, such as FTP and HTTP.

/tmp

This directory is used by programs that require temporary storage of files.

Important
Important: Cleaning up /tmp at boot time

Data stored in /tmp is not guaranteed to survive a system reboot. It depends, for example, on settings made in /etc/tmpfiles.d/tmp.conf.

/usr

/usr has nothing to do with users, but is the acronym for Unix system resources. The data in /usr is static, read-only data that can be shared among various hosts compliant with the Filesystem Hierarchy Standard (FHS). This directory contains all application programs including the graphical desktops such as GNOME and establishes a secondary hierarchy in the file system. /usr holds several subdirectories, such as /usr/bin, /usr/sbin, /usr/local, and /usr/share/doc.

/usr/bin

Contains generally accessible programs.

/usr/sbin

Contains programs reserved for the system administrator, such as repair functions.

/usr/local

In this directory the system administrator can install local, distribution-independent extensions.

/usr/share/doc

Holds various documentation files and the release notes for your system. In the manual subdirectory find an online version of this manual. If more than one language is installed, this directory may contain versions of the manuals for different languages.

Under packages find the documentation included in the software packages installed on your system. For every package, a subdirectory /usr/share/doc/packages/PACKAGENAME is created that often holds README files for the package and sometimes examples, configuration files or additional scripts.

If HOWTOs are installed on your system /usr/share/doc also holds the howto subdirectory in which to find additional documentation on many tasks related to the setup and operation of Linux software.

/var

Whereas /usr holds static, read-only data, /var is for data which is written during system operation and thus is variable data, such as log files or spooling data. For an overview of the most important log files you can find under /var/log/, refer to Table 21.1, “Log files”.

/windows

Only available if you have both Microsoft Windows and Linux installed on your system. Contains the Windows data available on the Windows partition of your system. Whether you can edit the data in this directory depends on the file system your Windows partition uses. If it is FAT32, you can open and edit the files in this directory. For NTFS, openSUSE Leap also includes write access support. However, the driver for the NTFS-3g file system has limited functionality.

14.2 Writing shell scripts Edit source

Shell scripts provide a convenient way to perform a wide range of tasks: collecting data, searching for a word or phrase in a text and other useful things. The following example shows a small shell script that prints a text:

Example 14.1: A shell script printing a text
#!/bin/sh 1
# Output the following line: 2
echo "Hello World" 3

1

The first line begins with the Shebang characters (#!) which indicate that this file is a script. The interpreter, specified after the Shebang, executes the script. In this case, the specified interpreter is /bin/sh.

2

The second line is a comment beginning with the hash sign. We recommend that you comment difficult lines. With proper commenting, you can remember the purpose and function of the line. Also, other readers can better understand your script. Commenting is considered good practice in the development community.

3

The third line uses the built-in command echo to print the corresponding text.

Before you can run this script, there are a few prerequisites:

  1. Every script should contain a Shebang line (as in the example above). If the line is missing, you need to call the interpreter manually.

  2. You can save the script wherever you want. However, it is a good idea to save it in a directory where the shell can find it. The search path in a shell is determined by the environment variable PATH. A normal user does not have write access to /usr/bin. Therefore it is recommended to save your scripts in the users' directory ~/bin/. The above example gets the name hello.sh.

  3. The script needs executable permissions. Set the permissions with the following command:

    > chmod +x ~/bin/hello.sh

If you have fulfilled all the above prerequisites, you can execute the script in the following ways:

  1. As absolute path.  The script can be executed with an absolute path. In our case, it is ~/bin/hello.sh.

  2. Everywhere.  If the PATH environment variable contains the directory where the script is located, you can execute the script with hello.sh.

14.3 Redirecting command events Edit source

Each command can use three channels, either for input or output:

  • Standard output.  This is the default output channel. Whenever a command prints something, it uses the standard output channel.

  • Standard input.  If a command needs input from users or other commands, it uses this channel.

  • Standard error.  Commands use this channel for error reporting.

To redirect these channels, there are the following possibilities:

Command > File

Saves the output of the command into a file, the existing file is deleted. For example, the ls command writes its output into the file listing.txt:

> ls > listing.txt
Command >> File

Appends the output of the command to a file. For example, the ls command appends its output to the file listing.txt:

> ls >> listing.txt
Command < File

Reads the file as input for the given command. For example, the read command reads in the content of the file into the variable:

> read a < foo
Command1 | Command2

Redirects the output of the left command as input for the right command. For example, the cat command outputs the content of the /proc/cpuinfo file. This output is used by grep to filter only those lines which contain cpu:

> cat /proc/cpuinfo | grep cpu

Every channel has a file descriptor: 0 (zero) for standard input, 1 for standard output and 2 for standard error. It is allowed to insert this file descriptor before a < or > character. For example, the following line searches for a file starting with foo, but suppresses its errors by redirecting it to /dev/null:

> find / -name "foo*" 2>/dev/null

14.4 Using aliases Edit source

An alias is a shortcut definition of one or more commands. The syntax for an alias is:

alias NAME=DEFINITION

For example, the following line defines an alias lt that outputs a long listing (option -l), sorts it by modification time (-t), and prints it in reverse sorted order (-r):

> alias lt='ls -ltr'

To view all alias definitions, use alias. Remove your alias with unalias and the corresponding alias name.

14.5 Using variables in Bash Edit source

A shell variable can be global or local. Global variables, or environment variables, can be accessed in all shells. In contrast, local variables are visible in the current shell only.

To view all environment variables, use the printenv command. If you need to know the value of a variable, insert the name of your variable as an argument:

> printenv PATH

A variable, be it global or local, can also be viewed with echo:

> echo $PATH

To set a local variable, use a variable name followed by the equal sign, followed by the value:

> PROJECT="SLED"

Do not insert spaces around the equal sign, otherwise you get an error. To set an environment variable, use export:

> export NAME="tux"

To remove a variable, use unset:

> unset NAME

The following table contains common environment variables that you can use in you shell scripts:

Table 14.5: Useful environment variables

HOME

the home directory of the current user

HOST

the current host name

LANG

when a tool is localized, it uses the language from this environment variable. English can also be set to C

PATH

the search path of the shell, a list of directories separated by colon

PS1

specifies the normal prompt printed before each command

PS2

specifies the secondary prompt printed when you execute a multi-line command

PWD

current working directory

USER

the current user

14.5.1 Using argument variables Edit source

For example, if you have the script foo.sh you can execute it like this:

> foo.sh "Tux Penguin" 2000

To access all the arguments which are passed to your script, you need positional parameters. These are $1 for the first argument, $2 for the second, and so on. You can have up to nine parameters. To get the script name, use $0.

The following script foo.sh prints all arguments from 1 to 4:

#!/bin/sh
echo \"$1\" \"$2\" \"$3\" \"$4\"

If you execute this script with the above arguments, you get:

"Tux Penguin" "2000" "" ""

14.5.2 Using variable substitution Edit source

Variable substitutions apply a pattern to the content of a variable either from the left or right side. The following list contains the possible syntax forms:

${VAR#pattern}

removes the shortest possible match from the left:

> file=/home/tux/book/book.tar.bz2
> echo ${file#*/}
home/tux/book/book.tar.bz2
${VAR##pattern}

removes the longest possible match from the left:

> file=/home/tux/book/book.tar.bz2
> echo ${file##*/}
book.tar.bz2
${VAR%pattern}

removes the shortest possible match from the right:

> file=/home/tux/book/book.tar.bz2
> echo ${file%.*}
/home/tux/book/book.tar
${VAR%%pattern}

removes the longest possible match from the right:

> file=/home/tux/book/book.tar.bz2
> echo ${file%%.*}
/home/tux/book/book
${VAR/pattern_1/pattern_2}

substitutes the content of VAR from the PATTERN_1 with PATTERN_2:

> file=/home/tux/book/book.tar.bz2
> echo ${file/tux/wilber}
/home/wilber/book/book.tar.bz2

14.6 Grouping and combining commands Edit source

Shells allow you to concatenate and group commands for conditional execution. Each command returns an exit code which determines the success or failure of its operation. If it is 0 (zero) the command was successful, everything else marks an error which is specific to the command.

The following list shows, how commands can be grouped:

Command1 ; Command2

executes the commands in sequential order. The exit code is not checked. The following line displays the content of the file with cat and then prints its file properties with ls regardless of their exit codes:

> cat filelist.txt ; ls -l filelist.txt
Command1 && Command2

runs the right command, if the left command was successful (logical AND). The following line displays the content of the file and prints its file properties only, when the previous command was successful (compare it with the previous entry in this list):

> cat filelist.txt && ls -l filelist.txt
Command1 || Command2

runs the right command, when the left command has failed (logical OR). The following line creates only a directory in /home/wilber/bar when the creation of the directory in /home/tux/foo has failed:

> mkdir /home/tux/foo || mkdir /home/wilber/bar
funcname(){ ... }

creates a shell function. You can use the positional parameters to access its arguments. The following line defines the function hello to print a short message:

> hello() { echo "Hello $1"; }

You can call this function like this:

> hello Tux

which prints:

Hello Tux

14.7 Working with common flow constructs Edit source

To control the flow of your script, a shell has while, if, for and case constructs.

14.7.1 The if control command Edit source

The if command is used to check expressions. For example, the following code tests whether the current user is Tux:

if test $USER = "tux"; then
  echo "Hello Tux."
else
  echo "You are not Tux."
fi

The test expression can be as complex or simple as possible. The following expression checks if the file foo.txt exists:

if test -e /tmp/foo.txt ; then
  echo "Found foo.txt"
fi

The test expression can also be abbreviated in square brackets:

if [ -e /tmp/foo.txt ] ; then
  echo "Found foo.txt"
fi

Find more useful expressions at https://bash.cyberciti.biz/guide/If..else..fi.

14.7.2 Creating loops with the for command Edit source

The for loop allows you to execute commands to a list of entries. For example, the following code prints certain information about PNG files in the current directory:

for i in *.png; do
 ls -l $i
done

14.8 More information Edit source

Important information about Bash is provided in the man pages man bash. More about this topic can be found in the following list:

Part V Hardware configuration Edit source

15 Setting up your system keyboard layout

The YaST System Keyboard Layout module lets you define the default keyboard layout for the system (also used for the console). Users can modify the keyboard layout in their individual X sessions, using the desktop's tools.

16 Setting up sound cards

YaST detects most sound cards automatically and configures them with the appropriate values. To change the default settings, or to set up a sound card that could not be configured automatically, use the YaST sound module. There, you can also set up additional sound cards or switch their order.

17 Setting up a printer

YaST can be used to configure local and network printers. Further information about printing (general information, technical details, and troubleshooting) is available in Chapter 7, Printer operation.

18 Setting up a scanner

You can configure a USB or SCSI scanner with YaST. The sane-backends package contains hardware drivers and other essentials needed to use a scanner. If you own an HP All-In-One device, see Section 18.1, “Configuring an HP all-in-one device”, instructions on how to configure a network scanner are ava…

19 Persistent memory

This chapter contains additional information about using openSUSE Leap with non-volatile main memory, also known as Persistent Memory, comprising one or more NVDIMMs.

15 Setting up your system keyboard layout Edit source

The YaST System Keyboard Layout module lets you define the default keyboard layout for the system (also used for the console). Users can modify the keyboard layout in their individual X sessions, using the desktop's tools.

  1. Start the YaST System Keyboard Configuration dialog by clicking Hardware › System Keyboard Layout in YaST. Alternatively, start the module from the command line with sudo yast2 keyboard.

  2. Select the desired Keyboard Layout from the list.

  3. Try the selected keyboard layout in the Test text box.

  4. If the result is as expected, confirm your changes and close the dialog.

  5. The result is stored in the files /etc/vconsole.conf (for text consoles) and /etc/X11/xorg.conf.d/00-keyboard.conf (for X11).

  6. Advanced keyboard settings can be configured in System › Sysconfig Editor › Hardware › Keyboard. Here you can specify the keyboard rate and delay settings, and enable or disable NumLock, CapsLock, and ScrollLock. These settings are stored in /etc/sysconfig/keyboard.

16 Setting up sound cards Edit source

YaST detects most sound cards automatically and configures them with the appropriate values. To change the default settings, or to set up a sound card that could not be configured automatically, use the YaST sound module. There, you can also set up additional sound cards or switch their order.

Warning
Warning

If you do not know all details about the setup of your sound system, do not change its settings manually. Instead, let your sound subsystem—PipeWire or PulseAudio— configure it for you. Use dedicated desktop application to switch audio devices. As a fallback, use the pavucontrol graphical application.

To start the sound module, start YaST and click Hardware › Sound. Alternatively, start the Sound Configuration dialog directly by running yast2 sound & as user root from a command line. If the sound module is not available, install it using the sudo zypper install yast2-sound command.

Procedure 16.1: Configuring sound cards

If you have added a new sound card or YaST could not automatically configure an existing sound card, follow the steps below. For configuring a new sound card, you need to know your sound card vendor and model. If in doubt, refer to your sound card documentation for the required information. For a reference list of sound cards supported by ALSA with their corresponding sound modules, see https://www.alsa-project.org/main/index.php/Matrix:Main.

During configuration, you can choose between the following setup options:

Quick automatic setup

You are not required to go through any of the further configuration steps—the sound card is configured automatically. You can set the volume or any options you want to change later.

Normal setup

Allows you to adjust the output volume and play a test sound during the configuration.

Advanced setup with possibility to change options

For experts only. Allows you to customize all parameters of the sound card.

Important
Important: Advanced configuration

Only use this option if you know exactly what you are doing. Otherwise leave the parameters untouched and use the normal or the automatic setup options.

  1. Start the YaST sound module.

  2. To configure a detected, but Not Configured sound card, select the respective entry from the list and click Edit.

    To configure a new sound card, click Add. Select your sound card vendor and model and click Next.

  3. Choose one of the setup options and click Next.

  4. If you have chosen Normal Setup, you can now Test your sound configuration and make adjustments to the volume. You should start at about ten percent volume to avoid damage to your hearing or the speakers.

  5. If all options are set according to your wishes, click Next.

    The Sound Configuration dialog shows the newly configured or modified sound card.

  6. To remove a sound card configuration that you no longer need, select the respective entry and click Delete.

  7. Click OK to save the changes and leave the YaST sound module.

Procedure 16.2: Modifying sound card configurations
  1. To change the configuration of an individual sound card (for experts only!), select the sound card entry in the Sound Configuration dialog and click Edit.

    This takes you to the Sound Card Advanced Options where you can fine-tune several parameters. For more information, click Help.

  2. To adjust the volume of an already configured sound card or to test the sound card, select the sound card entry in the Sound Configuration dialog and click Other. Select the respective menu item.

    Note
    Note: YaST mixer

    The YaST mixer settings provide only basic options. They are intended for troubleshooting (for example, if the test sound is not audible). Access the YaST mixer settings from Other › Volume. For everyday use and fine-tuning of sound options, use the mixer applet provided by your desktop or the alsasound command line tool.

  3. For playback of MIDI files, select Other › Start Sequencer.

  4. When a supported sound card is detected, you can install SoundFonts for playback of MIDI files:

    1. Insert the original driver CD-ROM into your CD or DVD drive.

    2. Select Other › Install SoundFonts to copy SF2 SoundFonts™ to your hard disk. The SoundFonts are saved in the directory /usr/share/sfbank/creative/.

  5. If you have configured more than one sound card in your system you can adjust the order of your sound cards. To set a sound card as primary device, select the sound card in the Sound Configuration and click Other › Set as the Primary Card. The sound device with index 0 is the default device and thus used by the system and the applications.

  6. By default, openSUSE Leap uses the PulseAudio sound system. This is an abstraction layer that helps to mix multiple audio streams, bypassing any restrictions the hardware may have. To enable or disable the PulseAudio sound system, click Other › PulseAudio Configuration. If enabled, PulseAudio daemon is used to play sounds. Disable PulseAudio Support to use something else system-wide.

The volume and configuration of all sound cards are saved when you click OK and leave the YaST sound module. The mixer settings are saved to the file /etc/asound.state. The ALSA configuration data is appended to the end of the file /etc/modprobe.d/sound and written to /etc/sysconfig/sound.

17 Setting up a printer Edit source

YaST can be used to configure local and network printers. Further information about printing (general information, technical details, and troubleshooting) is available in Chapter 7, Printer operation.

In YaST, click Hardware › Printer to start the printer module. By default it opens in the Printer Configurations view, displaying a list of all printers that are available and configured. This is especially useful when having access to a lot of printers via the network. From here you can also Print a Test Page and configure printers.

Note
Note: Starting CUPS

To use the printer connected to your machine, you must have CUPS installed and running on your system. If CUPS is not running, you are prompted to start it. In case CUPS is not started at boot time, you are also prompted to enable it (recommended).

17.1 Configuring printers Edit source

Normally USB printers are detected automatically. If that does not happen, check whether the printer is switched on and connected to the machine.

Configuring a printer is a three-step process: specify the connection type, choose a driver, and name the print queue for this setup.

Many printer models may have several available drivers. When configuring the printer, YaST defaults to those marked recommended. Normally, it is not necessary to change the driver. However, if you want a color printer to print only in black and white, you can use a driver that does not support color printing. If you experience performance problems with a PostScript printer when printing graphics, try switching from a PostScript to a PCL driver (provided your printer understands PCL).

If no driver for your printer is listed, try selecting a generic driver with an appropriate standard language from the list. Refer to your printer's documentation to find out what language (the set of commands controlling the printer) your printer supports. If this does not work, refer to Section 17.1.1, “Adding drivers with YaST” for an alternative solution.

A printer is always used through a print queue. This ensures that simultaneous jobs can be queued and processed one by one. Each print queue is assigned to a specific driver, and a printer can have multiple queues. As an example, this makes it possible to set up a second queue on a color printer that prints black and white only. Refer to Section 7.1, “The CUPS workflow” for more information about print queues.

Procedure 17.1: Adding a new printer
  1. Start the YaST printer module with Hardware › Printer.

  2. In the Printer Configurations screen click Add.

  3. If the printer is already listed under Specify the Connection, proceed with the next step. Otherwise, try Detect More or start the Connection Wizard.

  4. In the text box under Find and Assign a Driver enter the vendor name and the model name and click Search for.

  5. Choose a driver that matches your printer. It is recommended to choose the driver listed first. If no suitable driver is displayed, try the following.

    1. Check the search term.

    2. Expand the search by clicking Find More.

    3. Add a driver as described in Section 17.1.1, “Adding drivers with YaST”.

  6. Specify the Default paper size.

  7. In the Set Arbitrary Name field, enter a unique name for the print queue.

  8. The printer is now configured with the default settings and ready to use. Click OK to return to the Printer Configurations view. The newly configured printer is now visible in the list of printers.

17.1.1 Adding drivers with YaST Edit source

Not all printer drivers available for openSUSE Leap are installed by default. When adding a printer, if no suitable driver is available in the Find and Assign a Driver dialog, install a driver package containing drivers for the printer:

Procedure 17.2: Installing additional driver packages
  1. Start the YaST printer module with Hardware › Printer.

  2. In the Printer Configurations screen, click Add.

  3. In the Find and Assign a Driver section, click Driver Packages.

  4. Choose one or more suitable driver packages from the list. Do not specify the path to a printer description file.

  5. Choose OK and confirm the package installation.

  6. To directly use these drivers, proceed as described in Procedure 17.1, “Adding a new printer”.

PostScript printers do not need printer driver software. PostScript printers need only a PostScript Printer Description (PPD) file which matches the particular model. PPD files are provided by the printer manufacturer.

If no suitable PPD file is available in the Find and Assign a Driver dialog when adding a PostScript printer, install a PPD file for your printer:

There are several sources of PPD files. It is recommended to first try additional driver packages that are shipped with openSUSE Leap but not installed by default (see below for installation instructions). If these packages do not contain suitable drivers for your printer, get PPD files directly from your printer vendor or from the driver CD of a PostScript printer. For details, see Section 7.8.2, “No suitable PPD file available for a PostScript printer”. Alternatively, find PPD files at https://www.openprinting.org/printers, the OpenPrinting.org printer database. When using PPD files from OpenPrinting, keep in mind that they may not be supported by openSUSE Leap.

Procedure 17.3: Adding a PPD file for PostScript printers
  1. Start the YaST printer module with Hardware › Printer.

  2. In the Printer Configurations screen, click Add.

  3. In the Find and Assign a Driver section, click Driver Packages.

  4. Enter the full path to the PPD file into the text box under Make a Printer Description File Available.

  5. Click OK to return to the Add New Printer Configuration screen.

  6. To directly use this PPD file, proceed as described in Procedure 17.1, “Adding a new printer”.

17.1.2 Editing a local printer configuration Edit source

By editing an existing configuration for a printer you can change basic settings such as connection type and driver. It is also possible to adjust the default settings for paper size, resolution, media source, etc. You can change identifiers of the printer by altering the printer description or location.

  1. Start the YaST printer module with Hardware › Printer.

  2. In the Printer Configurations screen, choose a local printer configuration from the list and click Edit.

  3. Change the connection type or the driver as described in Procedure 17.1, “Adding a new printer”. This should only be necessary in case you have problems with the current configuration.

  4. Optionally, make this printer the default by checking Default Printer.

  5. Adjust default settings by clicking All Options for the Current Driver. To change a setting, expand the list of options by clicking the + sign. Change the default by clicking an option. Apply your changes with OK.

17.2 Configuring printing via the network with YaST Edit source

Network printers are not detected automatically. They must be configured manually using the YaST printer module. Depending on your network setup, you can print to a print server (CUPS, LPD, SMB or IPX) or directly to a network printer (preferably via TCP). Access the configuration view for network printing by choosing Printing via Network from the left pane in the YaST printer module.

17.2.1 Using CUPS Edit source

In a Linux environment CUPS is used to print via the network. The simplest setup is to only print via a single CUPS server which can directly be accessed by all clients. Printing via more than one CUPS server requires a running local CUPS daemon that communicates with the remote CUPS servers.

Important
Important: Browsing network print queues

CUPS servers announce their print queues over the network either via the traditional CUPS browsing protocol or via Bonjour/DNS-SD. Clients need to browse these lists so users can select specific printers to send their print jobs to. To browse network print queues, the service cups-browsed provided by the package cups-filters-cups-browsed must run on all clients that print via CUPS servers. cups-browsed is started automatically when configuring network printing with YaST.

If browsing does not work after starting cups-browsed, the CUPS servers may announce the network print queues via Bonjour/DNS-SD. In this case you need to additionally install the package avahi and start the associated service with sudo systemctl start avahi-daemon on all clients.

Procedure 17.4: Printing via a single CUPS server
  1. Start the YaST printer module with Hardware › Printer.

  2. From the left pane, select Print via Network.

  3. Check Do All Your Printing Directly via One Single CUPS Server and specify the name or IP address of the server.

  4. Click Test Server to make sure you have chosen the correct name or IP address.

  5. Click OK to return to the Printer Configurations screen. All printers available via the CUPS server are now listed.

Procedure 17.5: Printing via multiple CUPS servers
  1. Start the YaST printer module with Hardware › Printer.

  2. From the left pane, select Print via Network.

  3. Check Accept Printer Announcements from CUPS Servers.

  4. Under General Settings specify which servers to use. You may accept connections from all networks available or from specific hosts. If you choose the latter option, you need to specify the host names or IP addresses.

  5. Click OK and then Yes when prompted to start a local CUPS server. After the server has started, YaST returns to the Printer Configurations screen. Click Refresh list to see the printers detected so far.

17.2.2 Using print servers other than CUPS Edit source

If your network offers print services via print servers other than CUPS, start the YaST printer module with Hardware › Printer and select Print via Network from the left pane. Start the Connection Wizard and choose the appropriate Connection Type. Ask your network administrator for details on configuring a network printer in your environment.

17.3 Sharing printers over the network Edit source

Printers managed by a local CUPS daemon can be shared over the network, effectively turning your machine into a CUPS server. You share a printer by enabling so-called browsing mode in CUPS. If browsing is enabled, the local print queues are made available on the network for listening to remote CUPS daemons. It is also possible to set up a dedicated CUPS server that manages all print queues and can be accessed by remote clients directly. In this case, enabling browsing is not required.

Procedure 17.6: Sharing printers
  1. Start the YaST printer module with Hardware › Printer.

  2. Select Share Printers from the left pane.

  3. Select Allow Remote Access. Also check For computers within the local network and enable browsing mode by also checking Publish printers by default within the local network.

  4. Click OK to restart the CUPS server and to return to the Printer Configurations screen.

  5. Regarding CUPS and firewall settings, see https://en.opensuse.org/SDB:CUPS_and_SANE_Firewall_settings.

18 Setting up a scanner Edit source

You can configure a USB or SCSI scanner with YaST. The sane-backends package contains hardware drivers and other essentials needed to use a scanner. If you own an HP All-In-One device, see Section 18.1, “Configuring an HP all-in-one device”, instructions on how to configure a network scanner are available at Section 18.3, “Scanning over the network”.

Procedure 18.1: Configuring a USB or SCSI scanner
  1. Connect your USB or SCSI scanner to your computer and turn it on.

  2. Start YaST and select Hardware › Scanner. YaST builds the scanner database and tries to detect your scanner model automatically.

    If a USB or SCSI scanner is not properly detected, try Other › Restart Detection.

  3. To activate the scanner select it from the list of detected scanners and click Edit.

  4. Choose your model form the list and click Next and Finish.

  5. Use Other › Test to make sure you have chosen the correct driver.

  6. Leave the configuration screen with OK.

18.1 Configuring an HP all-in-one device Edit source

An HP All-In-One device can be configured with YaST even if it is made available via the network. If you own a USB HP All-In-One device, start configuring as described in Procedure 18.1, “Configuring a USB or SCSI scanner”. If it is detected properly and the Test succeeds, it is ready to use.

If your USB device is not properly detected, or your HP All-In-One device is connected to the network, run the HP Device Manager:

  1. Start YaST and select Hardware › Scanner. YaST loads the scanner database.

  2. Start the HP Device Manager with Other › Run hp-setup and follow the on-screen instructions. After having finished the HP Device Manager, the YaST scanner module automatically restarts the auto detection.

  3. Test it by choosing Other › Test.

  4. Leave the configuration screen with OK.

18.2 Sharing a scanner over the network Edit source

openSUSE Leap allows the sharing of a scanner over the network. To do so, configure your scanner as follows:

  1. Configure the scanner as described in Chapter 18, Setting up a scanner.

  2. Choose Other › Scanning via Network.

  3. Enter the host names of the clients (separated by a comma) that should be allowed to use the scanner under Server Settings › Permitted Clients for saned and leave the configuration dialog with OK.

18.3 Scanning over the network Edit source

To use a scanner that is shared over the network, proceed as follows:

  1. Start YaST and select Hardware › Scanner.

  2. Open the network scanner configuration menu by Other › Scanning via Network.

  3. Enter the host name of the machine the scanner is connected to under Client Settings › Servers Used for the net Metadriver

  4. Leave with OK. The network scanner is now listed in the Scanner Configuration window and is ready to use.

19 Persistent memory Edit source

Abstract

This chapter contains additional information about using openSUSE Leap with non-volatile main memory, also known as Persistent Memory, comprising one or more NVDIMMs.

19.1 Introduction Edit source

Persistent memory is a new type of computer storage, combining speeds approaching those of dynamic RAM (DRAM) along with RAM's byte-by-byte addressability, plus the permanence of solid-state drives (SSDs).

SUSE currently supports the use of persistent memory with openSUSE Leap on machines with the AMD64/Intel 64 and POWER architectures.

Like conventional RAM, persistent memory is installed directly into mainboard memory slots. As such, it is supplied in the same physical form factor as RAM—as DIMMs. These are known as NVDIMMs: non-volatile dual inline memory modules.

Unlike RAM, though, persistent memory is also similar to flash-based SSDs in several ways. Both are based on forms of solid-state memory circuitry, but despite this, both provide non-volatile storage: Their contents are retained when the system is powered off or restarted. For both forms of medium, writing data is slower than reading it, and both support a limited number of rewrite cycles. Finally, also like SSDs, sector-level access to persistent memory is possible if that is more suitable for a particular application.

Different models use different forms of electronic storage medium, such as Intel 3D XPoint, or a combination of NAND-flash and DRAM. New forms of non-volatile RAM are also in development. This means that different vendors and models of NVDIMM offer different performance and durability characteristics.

Because the storage technologies involved are in an early stage of development, different vendors' hardware may impose different limitations. Thus, the following statements are generalizations.

Persistent memory is up to ten times slower than DRAM, but around a thousand times faster than flash storage. It can be rewritten on a byte-by-byte basis rather than flash memory's whole-sector erase-and-rewrite process. Finally, while rewrite cycles are limited, most forms of persistent memory can handle millions of rewrites, compared to the thousands of cycles of flash storage.

This has two important consequences:

  • It is not possible with current technology to run a system with only persistent memory and thus achieve non-volatile main memory. You must use a mixture of both conventional RAM and NVDIMMs. The operating system and applications will execute in conventional RAM, with the NVDIMMs providing fast supplementary storage.

  • The performance characteristics of different vendors' persistent memory mean that it may be necessary for programmers to be aware of the hardware specifications of the NVDIMMs in a particular server, including how many NVDIMMs there are and in which memory slots they are fitted. This will impact hypervisor use, migration of software between different host machines, and so on.

This new storage subsystem is defined in version 6 of the ACPI standard. However, libnvdimm supports pre-standard NVDIMMs and they can be used in the same way.

Tip
Tip: Intel Optane DC Persistent Memory

Intel Optane DIMMs memory can be used in specific modes:

  • In App Direct Mode, the Intel Optane memory is used as fast persistent storage, an alternative to SSDs and NVMe devices. Data in this mode is kept when the system is powered off.

  • In Memory Mode, the Intel Optane memory serves as a cost-effective, high-capacity alternative to DRAM. In this mode, separate DRAM DIMMs act as a cache for the most frequently accessed data while the Optane DIMMs memory provides large memory capacity. However, compared with DRAM-only systems, this mode is slower under random access workloads. If you run applications without Optane-specific enhancements that take advantage of this mode, memory performance may decrease. Data in this mode is lost when the system is powered off.

  • In Mixed Mode, the Intel Optane memory is partitioned, so it can serve in both modes simultaneously.

19.2 Terms Edit source

Region

A region is a block of persistent memory that can be divided up into one or more namespaces. You cannot access the persistent memory of a region without first allocating it to a namespace.

Namespace

A single contiguously addressed range of non-volatile storage, comparable to NVM Express SSD namespaces, or to SCSI Logical Units (LUNs). Namespaces appear in the server's /dev directory as separate block devices. Depending on the method of access required, namespaces can either amalgamate storage from multiple NVDIMMs into larger volumes, or allow it to be partitioned into smaller volumes.

Mode

Each namespace also has a mode that defines which NVDIMM features are enabled for that namespace. Sibling namespaces of the same parent region always have the same type, but might be configured to have different modes. Namespace modes include:

devdax

Device-DAX mode. Creates a single-character device file ( /dev/daxX.Y ). Does not require file system creation.

fsdax

File system-DAX mode. Default if no other mode is specified. Creates a block device (/dev/pmemX [.Y]) which supports DAX for ext4 or XFS.

sector

For legacy file systems which do not checksum metadata. Suitable for small boot volumes. Compatible with other operating systems.

raw

A memory disk without a label or metadata. Does not support DAX. Compatible with other operating systems.

Note
Note

raw mode is not supported by SUSE. It is not possible to mount file systems on raw namespaces.

Type

Each namespace and region has a type that defines how the persistent memory associated with that namespace or region can be accessed. A namespace always has the same type as its parent region. There are two different types: Persistent Memory, which can be configured in two different ways, and the deprecated Block Mode.

Persistent memory (PMEM)

PMEM storage offers byte-level access, similar to RAM. Using PMEM, a single namespace can include multiple interleaved NVDIMMs, allowing them all to be used as a single device.

There are two ways to configure a PMEM namespace.

PMEM with DAX

A PMEM namespace configured for Direct Access (DAX) means that accessing the memory bypasses the kernel's page cache and goes direct to the medium. Software can directly read or write every byte of the namespace separately.

PMEM with block translation table (BTT)

A PMEM namespace configured to operate in BTT mode is accessed on a sector-by-sector basis, like a conventional disk drive, rather than the more RAM-like byte-addressable model. A translation table mechanism batches accesses into sector-sized units.

The advantage of BTT is data protection. The storage subsystem ensures that each sector is completely written to the underlying medium. If a sector cannot be completely written (that is, if the write operation fails for some reason), then the whole sector will be rolled back to its previous state. Thus a given sector cannot be partially written.

Additionally, access to BTT namespaces is cached by the kernel.

The drawback is that DAX is not possible for BTT namespaces.

Block mode (BLK)

Block mode storage addresses each NVDIMM as a separate device. Its use is deprecated and no longer supported.

Apart from devdax namespaces, all other types must be formatted with a file system, just as with a conventional drive. openSUSE Leap supports the ext2, ext4 and XFS file systems for this.

Direct access (DAX)

DAX allows persistent memory to be directly mapped into a process's address space, for example, using the mmap system call.

DIMM physical address (DPA)

A memory address as an offset into a single DIMM's memory; that is, starting from zero as the lowest addressable byte on that DIMM.

Label

Metadata stored on the NVDIMM, such as namespace definitions. This can be accessed using DSMs.

Device-specific method (DSM)

ACPI method to access the firmware on an NVDIMM.

19.3 Use cases Edit source

19.3.1 PMEM with DAX Edit source

This form of memory access is not transactional. In the event of a power outage or other system failure, data may not be written into storage. PMEM storage is only suitable if the application can handle the situation of partially written data.

19.3.1.1 Applications that benefit from large amounts of byte-addressable storage Edit source

If the server will host an application that can directly use large amounts of fast storage on a byte-by-byte basis, the programmer can use the mmap system call to place blocks of persistent memory directly into the application's address space, without using any additional system RAM.

19.3.1.2 Avoiding use of the kernel page cache Edit source

Avoid using the kernel page cache to conserve the use of RAM for the page cache, and instead give it to your applications. For instance, non-volatile memory could be dedicated to holding virtual machine (VM) images. As these would not be cached, this would reduce the cache usage on the host, allowing more VMs per host.

19.3.2 PMEM with BTT Edit source

This is useful when you want to use the persistent memory on a set of NVDIMMs as a disk-like pool of fast storage. For example, placing the file system journal on PMEM with BTT increases the reliability of file system recovery after a power failure or other sudden interruption (see Section 19.5.3, “Creating a PMEM namespace with BTT”).

To applications, such devices appear as fast SSDs and can be used like any other storage device. For example, LVM can be layered on top of the persistent memory and will work as normal.

The advantage of BTT is that sector write atomicity is guaranteed, so even sophisticated applications that depend on data integrity will keep working. Media error reporting works through standard error-reporting channels.

19.4 Tools for managing persistent memory Edit source

To manage persistent memory, it is necessary to install the ndctl package. This also installs the libndctl package, which provides a set of user space libraries to configure NVDIMMs.

These tools work via the libnvdimm library, which supports three types of NVDIMM:

  • PMEM

  • BLK

  • Simultaneous PMEM and BLK

The ndctl utility has a helpful set of man pages, accessible with the command:

> ndctl help subcommand

To see a list of available subcommands, use:

> ndctl --list-cmds

The available subcommands include:

version

Displays the current version of the NVDIMM support tools.

enable-namespace

Makes the specified namespace available for use.

disable-namespace

Prevents the specified namespace from being used.

create-namespace

Creates a new namespace from the specified storage devices.

destroy-namespace

Removes the specified namespace.

enable-region

Makes the specified region available for use.

disable-region

Prevents the specified region from being used.

zero-labels

Erases the metadata from a device.

read-labels

Retrieves the metadata of the specified device.

list

Displays available devices.

help

Displays information about using the tool.

19.5 Setting up persistent memory Edit source

19.5.1 Viewing available NVDIMM storage Edit source

The ndctl list command can be used to list all available NVDIMMs in a system.

In the following example, the system has three NVDIMMs, which are in a single, triple-channel interleaved set.

# ndctl list --dimms

[
 {
  "dev":"nmem2",
  "id":"8089-00-0000-12325476"
 },
 {
  "dev":"nmem1",
  "id":"8089-00-0000-11325476"
 },
 {
  "dev":"nmem0",
  "id":"8089-00-0000-10325476"
 }
]

With a different parameter, ndctl list will also list the available regions.

Note
Note

Regions may not appear in numerical order.

Note that although there are only three NVDIMMs, they appear as four regions.

# ndctl list --regions

[
 {
  "dev":"region1",
  "size":68182605824,
  "available_size":68182605824,
  "type":"blk"
 },
 {
  "dev":"region3",
  "size":202937204736,
  "available_size":202937204736,
  "type":"pmem",
  "iset_id":5903239628671731251
  },
  {
   "dev":"region0",
   "size":68182605824,
   "available_size":68182605824,
   "type":"blk"
  },
  {
   "dev":"region2",
   "size":68182605824,
   "available_size":68182605824,
   "type":"blk"
  }
]

The space is available in two different forms: either as three separate 64 regions of type BLK, or as one combined 189 GB region of type PMEM which presents all the space on the three interleaved NVDIMMs as a single volume.

Note that the displayed value for available_size is the same as that for size. This means that none of the space has been allocated yet.

19.5.2 Configuring the storage as a single PMEM namespace with DAX Edit source

For the first example, we will configure our three NVDIMMs into a single PMEM namespace with Direct Access (DAX).

The first step is to create a new namespace.

# ndctl create-namespace --type=pmem --mode=fsdax --map=memory
{
 "dev":"namespace3.0",
 "mode":"memory",
 "size":199764213760,
 "uuid":"dc8ebb84-c564-4248-9e8d-e18543c39b69",
 "blockdev":"pmem3"
}

This creates a block device /dev/pmem3, which supports DAX. The 3 in the device name is inherited from the parent region number, in this case region3.

The --map=memory option sets aside part of the PMEM storage space on the NVDIMMs so that it can be used to allocate internal kernel data structures called struct pages. This allows the new PMEM namespace to be used with features such as O_DIRECT I/O and RDMA.

The reservation of some persistent memory for kernel data structures is why the resulting PMEM namespace has a smaller capacity than the parent PMEM region.

Next, we verify that the new block device is available to the operating system:

# fdisk -l /dev/pmem3
Disk /dev/pmem3: 186 GiB, 199764213760 bytes, 390164480 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes

Before it can be used, like any other drive, it must be formatted. In this example, we format it with XFS:

# mkfs.xfs /dev/pmem3
meta-data=/dev/pmem3      isize=256    agcount=4, agsize=12192640 blks
         =                sectsz=4096  attr=2, projid32bit=1
         =                crc=0        finobt=0, sparse=0
data     =                bsize=4096   blocks=48770560, imaxpct=25
         =                sunit=0      swidth=0 blks
naming   =version 2       bsize=4096   ascii-ci=0 ftype=1
log      =internal log    bsize=4096   blocks=23813, version=2
         =                sectsz=4096  sunit=1 blks, lazy-count=1
realtime =none            extsz=4096   blocks=0, rtextents=0

Next, we can mount the new drive onto a directory:

# mount -o dax /dev/pmem3 /mnt/pmem3

Then we can verify that we now have a DAX-capable device:

# mount | grep dax
/dev/pmem3 on /mnt/pmem3 type xfs (rw,relatime,attr2,dax,inode64,noquota)

The result is that we now have a PMEM namespace formatted with the XFS file system and mounted with DAX.

Any mmap() calls to files in that file system will return virtual addresses that directly map to the persistent memory on our NVDIMMs, bypassing the page cache.

Any fsync or msync calls on files in that file system will still ensure that modified data has been fully written to the NVDIMMs. These calls flush the processor cache lines associated with any pages that have been modified in user space via mmap mappings.

19.5.2.1 Removing a namespace Edit source

Before creating any other type of volume that uses the same storage, we must unmount and then remove this PMEM volume.

First, unmount it:

# umount /mnt/pmem3

Then disable the namespace:

# ndctl disable-namespace namespace3.0
disabled 1 namespace

Then delete it:

# ndctl destroy-namespace namespace3.0
destroyed 1 namespace

19.5.3 Creating a PMEM namespace with BTT Edit source

BTT provides sector write atomicity, which makes it a good choice when you need data protection, , for Ext4 and XFS journals. If there is a power failure, the journals are protected and should be recoverable. The following examples show how to create a PMEM namespace with BTT in sector mode, and how to place the file system journal in this namespace.

# ndctl create-namespace --type=pmem --mode=sector
{
 "dev":"namespace3.0",
 "mode":"sector",
 "uuid":"51ab652d-7f20-44ea-b51d-5670454f8b9b",
 "sector_size":4096,
 "blockdev":"pmem3s"
}

Next, verify that the new device is present:

# fdisk -l /dev/pmem3s
Disk /dev/pmem3s: 188.8 GiB, 202738135040 bytes, 49496615 sectors
Units: sectors of 1 * 4096 = 4096 bytes
Sector size (logical/physical): 4096 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes

Like the DAX-capable PMEM namespace we previously configured, this BTT-capable PMEM namespace consumes all the available storage on the NVDIMMs.

Note
Note

The trailing s in the device name (/dev/pmem3s) stands for sector and can be used to easily distinguish namespaces that are configured to use the BTT.

The volume can be formatted and mounted as in the previous example.

The PMEM namespace shown here cannot use DAX. Instead it uses the BTT to provide sector write atomicity. On each sector write through the PMEM block driver, the BTT will allocate a new sector to receive the new data. The BTT atomically updates its internal mapping structures after the new data is fully written so the newly written data will be available to applications. If the power fails at any point during this process, the write will be lost and the application will have access to its old data, still intact. This prevents the condition known as torn sectors.

This BTT-enabled PMEM namespace can be formatted and used with a file system same as any other standard block device. It cannot be used with DAX. However, mmap mappings for files on this block device will use the page cache.

19.5.4 Placing the file system journal on PMEM/BTT Edit source

When you place the file system journal on a separate device, it must use the same file system block size as the file system. Most likely this is 4096, and you can find the block size with this command:

# blockdev --getbsz /dev/sda3

The following example creates a new Ext4 journal on a separate NVDIMM device, creates the file system on a SATA device, then attaches the new file system to the journal:

# mke2fs -b 4096 -O journal_dev /dev/pmem3s
# mkfs.ext4 -J device=/dev/pmem3s /dev/sda3

The following example creates a new XFS file system on a SATA drive, and creates the journal on a separate NVDIMM device:

# mkfs.xfs -l logdev=/dev/pmem3s  /dev/sda3

See man 8 mkfs.ext4 and man 8 mkfs.ext4 for detailed information about options.

19.6 More information Edit source

More about this topic can be found in the following list:

  • Persistent Memory Wiki

    Contains instructions for configuring NVDIMM systems, information about testing, and links to specifications related to NVDIMM enabling. This site is developing as NVDIMM support in Linux is developing.

  • Persistent Memory Programming

    Information about configuring, using and programming systems with non-volatile memory under Linux and other operating systems. Covers the NVM Library (NVML), which aims to provide useful APIs for programming with persistent memory in user space.

  • LIBNVDIMM: Non-Volatile Devices

    Aimed at kernel developers, this is part of the Documentation directory in the current Linux kernel tree. It talks about the different kernel modules involved in NVDIMM enablement, lays out technical details of the kernel implementation, and talks about the sysfsinterface to the kernel that is used by the ndctl tool.

  • GitHub: pmem/ndctl

    Utility library for managing the libnvdimm subsystem in the Linux kernel. Also contains user space libraries, as well as unit tests and documentation.

Part VI Help and troubleshooting Edit source

20 Help and documentation

openSUSE® Leap comes with several sources of information and documentation, available online or integrated into your installed system.

21 Common problems and their solutions

This chapter describes a range of potential problems and their solutions. Even if your situation is not precisely listed, there may be one similar enough to offer hints to the solution of your problem.

20 Help and documentation Edit source

openSUSE® Leap comes with several sources of information and documentation, available online or integrated into your installed system.

Product Documentation

Extensive documentation for openSUSE Leap is available at https://doc.opensuse.org. Topics covered range from deployment, upgrade and system administration to virtualization, system tuning and security, among others.

Documentation in /usr/share/doc

This directory holds release notes for your system (in the subdirectory release-notes). It also contains information of installed packages in the subdirectory packages. Find more detailed information in Section 20.1, “Documentation directory”.

Man pages and info pages for shell commands

When working with the shell, you do not need to know the options of the commands by heart. Traditionally, the shell provides integrated help by means of man pages and info pages. Read more in Section 20.2, “Man pages” and Section 20.3, “Info pages”.

Desktop help center

The help center of the GNOME desktop (Help) provides central access to the GNOME desktop documentation.

Separate help packages for certain applications

When installing new software with YaST, the software documentation is normally installed automatically and appears in the help center of your desktop. However, certain applications, such as GIMP, may have different online help packages that can be installed separately with YaST and do not integrate into the help centers.

20.1 Documentation directory Edit source

The traditional directory to find documentation on your installed Linux system is /usr/share/doc. The directory contains the release notes and information about the packages installed on your system, plus manuals and more.

Note
Note: Contents depend on installed packages

In the Linux world, manuals and other kinds of documentation are available in the form of packages, like software. How much and which information you find in /usr/share/doc also depends on the (documentation) packages installed. If you cannot find the subdirectories mentioned here, check if the respective packages are installed on your system and add them with YaST, if needed.

20.1.1 Release notes Edit source

We provide HTML, PDF, RTF and text versions of openSUSE Leap release notes. They are available on your installed system under /usr/share/doc/release-notes/ or online at your product-specific Web page at https://doc.opensuse.org/release-notes/.

20.1.2 Package documentation Edit source

Under packages, find the documentation that is included in the software packages installed on your system. For every package, a subdirectory /usr/share/doc/packages/PACKAGENAME is created. It often contains README files for the package and sometimes examples, configuration files, or additional scripts. The following list introduces typical files to be found under /usr/share/doc/packages. None of these entries are mandatory and many packages only include a few of them.

AUTHORS

List of the main developers.

BUGS

Known bugs or malfunctions. May also contain a link to a Bugzilla Web page where you can search all bugs.

CHANGES , ChangeLog

Summary of changes from version to version. It is interesting for developers, because it is detailed.

COPYING , LICENSE

Licensing information.

FAQ

Question and answers collected from mailing lists or newsgroups.

INSTALL

How to install this package on your system. As the package is already installed by the time you get to read this file, you can safely ignore the contents of this file.

README, README.*

General information on the software. For example, for what purpose and how to use it.

TODO

Features planned for the future.

MANIFEST

List of files with a brief summary.

NEWS

Description of what is new in this version.

20.2 Man pages Edit source

Man pages are an essential part of any Linux system. They explain the usage of a command and all available options and parameters. Man pages can be accessed with man followed by the name of the command, for example, man ls.

Man pages are displayed directly in the shell. To navigate them, move up and down with Page ↑ and Page ↓. Move between the beginning and the end of a document with Home and End. End this viewing mode by pressing Q. Learn more about the man command itself with man man. Man pages are sorted in categories as shown in Table 20.1, “Man pages—categories and descriptions” (taken from the man page for man itself).

Table 20.1: Man pages—categories and descriptions

Number

Description

1

Executable programs or shell commands

2

System calls (functions provided by the kernel)

3

Library calls (functions within program libraries)

4

Special files (normally found in /dev)

5

File formats and conventions (/etc/fstab)

6

Games

7

Miscellaneous (including macro packages and conventions), for example, man(7), groff(7)

8

System administration commands (normally only for root)

9

Kernel routines (nonstandard)

Each man page consists of several parts labeled NAME, SYNOPSIS, DESCRIPTION, SEE ALSO, LICENSING, and AUTHOR. There may be additional sections available depending on the type of command.

20.3 Info pages Edit source

Info pages are another important source of information on your system. normally, they are more detailed than man pages. They consist of more than command line options and contain sometimes whole tutorials or reference documentation. To view the info page for a certain command, enter info followed by the name of the command, for example, info ls. You can browse an info page with a viewer directly in the shell and display the different sections, called nodes. Use Space to move forward and <— to move backward. Within a node, you can also browse with Page ↑ and Page ↓ but only Space and <— takes you also to the previous or subsequent node. Press Q to end the viewing mode. Not every command comes with an info page and vice versa.

20.4 Online resources Edit source

For an overview of all documentation available for openSUSE Leap check out the product-specific documentation Web pages at https://doc.opensuse.org/.

If you are searching for additional product-related information, you can also refer to the following Web sites:

User community

openSUSE Forums

GNOME documentation

Documentation for GNOME users, administrators and developers is available at https://help.gnome.org/.

The Linux documentation project

The Linux Documentation Project (TLDP) is run by a team of volunteers who write Linux-related documentation (see https://tldp.org/). It is a comprehensive documentation resource for Linux. The set of documents contains tutorials for beginners, but is mainly focused on experienced users and professional system administrators. TLDP publishes HOWTOs, FAQs and guides (handbooks) under a free license. Parts of the documentation from TLDP are also available on openSUSE Leap.

21 Common problems and their solutions Edit source

This chapter describes a range of potential problems and their solutions. Even if your situation is not precisely listed, there may be one similar enough to offer hints to the solution of your problem.

21.1 Finding and gathering information Edit source

Linux reports things in a detailed way. There are several places to look when you encounter problems with your system. Most of them are standard to Linux systems, and several are relevant to openSUSE Leap systems. Most log files can be viewed with YaST (Miscellaneous › Start-Up Log).

YaST offers the possibility to collect all system information needed by the support team. Use Other › Support and select the problem category. When all information is gathered, attach it to your support request.

A list of the most frequently checked log files follows with the description of their typical purpose. Paths containing ~ refer to the current user's home directory.

Table 21.1: Log files

Log File

Description

~/.xsession-errors

Messages from the desktop applications currently running.

/var/log/apparmor/

Log files from AppArmor, see Book “Security and Hardening Guide” for detailed information.

/var/log/audit/audit.log

Log file from Audit to track any access to files, directories, or resources of your system, and trace system calls. See Book “Security and Hardening Guide” for detailed information.

/var/log/mail.*

Messages from the mail system.

/var/log/NetworkManager

Log file from NetworkManager to collect problems with network connectivity

/var/log/samba/

Directory containing Samba server and client log messages.

/var/log/warn

All messages from the kernel and system log daemon with the warning level or higher.

/var/log/wtmp

Binary file containing user login records for the current machine session. View it with last.

/var/log/Xorg.*.log

Start-up and runtime log files from the X Window System. It is useful for debugging failed X start-ups.

/var/log/YaST2/

Directory containing YaST's actions and their results.

/var/log/zypper.log

Log file of Zypper.

Apart from log files, your machine also supplies you with information about the running system. See Table 21.2: System information with the /proc file system

Table 21.2: System information with the /proc file system

File

Description

/proc/cpuinfo

Contains processor information, including its type, make, model, and performance.

/proc/dma

Shows which DMA channels are currently being used.

/proc/interrupts

Shows which interrupts are in use, and how many of each have been in use.

/proc/iomem

Displays the status of I/O (input/output) memory.

/proc/ioports

Shows which I/O ports are in use at the moment.

/proc/meminfo

Displays memory status.

/proc/modules

Displays the individual modules.

/proc/mounts

Displays devices currently mounted.

/proc/partitions

Shows the partitioning of all hard disks.

/proc/version

Displays the current version of Linux.

Apart from the /proc file system, the Linux kernel exports information with the sysfs module, an in-memory file system. This module represents kernel objects, their attributes and relationships. For more information about sysfs, see the context of udev in Book “Reference”, Chapter 16 “Dynamic kernel device management with udev. Table 21.3 contains an overview of the most common directories under /sys.

Table 21.3: System information with the /sys file system

File

Description

/sys/block

Contains subdirectories for each block device discovered in the system. Generally, these are mostly disk type devices.

/sys/bus

Contains subdirectories for each physical bus type.

/sys/class

Contains subdirectories grouped together as a functional types of devices (like graphics, net, printer, etc.)

/sys/device

Contains the global device hierarchy.

Linux comes with several tools for system analysis and monitoring. See Book “System Analysis and Tuning Guide”, Chapter 2 “System monitoring utilities” for a selection of the most important ones used in system diagnostics.

Each of the following scenarios begins with a header describing the problem followed by a paragraph or two offering suggested solutions, available references for more detailed solutions, and cross-references to other scenarios that are related.

21.2 Boot problems Edit source

Boot problems are situations when your system does not boot properly (does not boot to the expected target and login screen).

21.2.1 The GRUB 2 boot loader fails to load Edit source

If the hardware is functioning properly, it is possible that the boot loader is corrupted and Linux cannot start on the machine. In this case, it is necessary to repair the boot loader. To do so, you need to start the Rescue System as described in Section 21.5.2, “Using the rescue system” and follow the instructions in Section 21.5.2.4, “Modifying and re-installing the boot loader”.

Alternatively, you can use the Rescue System to fix the boot loader as follows. Boot your machine from the installation media. In the boot screen, choose More › Boot Linux System. Select the disk containing the installed system and kernel with the default kernel options.

Select disk
Figure 21.1: Select disk

When the system is booted, start YaST and switch to System › Boot Loader. Make sure that the Write generic Boot Code to MBR option is enabled, and click OK. This fixes the corrupted boot loader by overwriting it, or installs the boot loader if it is missing.

Other reasons for the machine not booting may be BIOS-related:

BIOS settings

Check your BIOS for references to your hard disk. GRUB 2 may simply not be started if the hard disk itself cannot be found with the current BIOS settings.

BIOS boot order

Check whether your system's boot order includes the hard disk. If the hard disk option was not enabled, your system may install properly, but fails to boot when access to the hard disk is required.

21.2.2 No login or prompt appears Edit source

This behavior typically occurs after a failed kernel upgrade and it is known as a kernel panic because of the type of error on the system console that sometimes can be seen at the final stage of the process. If, in fact, the machine has just been rebooted following a software update, the immediate goal is to reboot it using the old, proven version of the Linux kernel and associated files. This can be done in the GRUB 2 boot loader screen during the boot process as follows:

  1. Reboot the computer using the reset button, or switch it off and on again.

  2. When the GRUB 2 boot screen becomes visible, select the Advanced Options entry and choose the previous kernel from the menu. The machine will boot using the prior version of the kernel and its associated files.

  3. After the boot process has completed, remove the newly installed kernel and, if necessary, set the default boot entry to the old kernel using the YaST Boot Loader module. For more information, refer to Book “Reference”, Chapter 12 “The boot loader GRUB 2”, Section 12.3 “Configuring the boot loader with YaST”. However, doing this is not necessary because automated update tools normally modify it for you during the rollback process.

  4. Reboot.

If this does not fix the problem, boot the computer using the installation media. After the machine has booted, continue with Step 3.

21.2.3 No graphical login Edit source

If the machine starts, but does not boot into the graphical login manager, anticipate problems either with the choice of the default systemd target or the configuration of the X Window System. To check the current systemd default target run the command sudo systemctl get-default. If the value returned is not graphical.target, run the command sudo systemctl isolate graphical.target. If the graphical login screen starts, log in and start YaST › System › Services Manager and set the Default System Target to Graphical Interface. From now on the system should boot into the graphical login screen.

If the graphical login screen does not start even if having booted or switched to the graphical target, your desktop or X Window software may be misconfigured or corrupted. Examine the log files at /var/log/Xorg.*.log for detailed messages from the X server as it attempted to start. If the desktop fails during start, it may log error messages to the system journal that can be queried with the command journalctl (see Book “Reference”, Chapter 11 “journalctl: query the systemd journal” for more information). If these error messages hint at a configuration problem in the X server, try to fix these issues. If the graphical system still does not come up, consider reinstalling the graphical desktop.

21.2.4 Root Btrfs partition cannot be mounted Edit source

If a btrfs root partition becomes corrupted, try the following options:

  • Mount the partition with the -o recovery option.

  • If that fails, run btrfs-zero-log on your root partition.

21.2.5 Force checking root partitions Edit source

If the root partition becomes corrupted, use the parameter forcefsck on the boot prompt. This passes the option -f (force) to the fsck command.

21.2.6 Disable swap to enable booting Edit source

When a swap device is not available and the system cannot enable it during boot, booting may fail. Try disabling all swap devices by appending the following options to the kernel command line:

systemd.device_wants_unit=off systemd.mask=swap.target

You may also try disabling specific swap devices:

systemd.mask=dev-sda1.swap

21.2.7 GRUB 2 fails during reboot on a dual-boot system Edit source

If GRUB 2 fails during reboot, disable the Fast Boot setting in the BIOS.

21.3 Login problems Edit source

Login problems occur when your system refuses to accept the user name and password, or accepts them but then fails to start the graphic desktop, produces errors, or drops to a command line, for example.

21.3.1 Valid user name and password combinations fail Edit source

This often occurs when the system is configured to use network authentication or directory services and cannot retrieve results from its configured servers. The root user is the only local user that can still log in to these machines. The following are common reasons a machine appears functional but cannot process logins correctly:

  • The network is not working. For further directions on this, turn to Section 21.4, “Network problems”.

  • DNS is not working at the moment (which prevents GNOME from working and the system from making validated requests to secure servers). One indication that this is the case is that the machine takes a long time to respond to any action. Find more information about this topic in Section 21.4, “Network problems”.

  • If the system is configured to use Kerberos, the system's local time may have drifted past the accepted variance with the Kerberos server time (this is typically 300 seconds). If NTP (network time protocol) is not working properly or local NTP servers are not working, Kerberos authentication ceases to function because it depends on common clock synchronization across the network.

  • The system's authentication configuration is misconfigured. Check the PAM configuration files involved for any typographical errors or misordering of directives. For additional background information about PAM and the syntax of the configuration files involved, refer to Book “Security and Hardening Guide”, Chapter 2 “Authentication with PAM”.

  • The home partition is encrypted. Find more information about this topic in Section 21.3.3, “Login to encrypted home partition fails”.

In cases that do not involve external network problems, the solution is to log in as root and repair the configuration. If you cannot log in to the running system, reboot it into the rescue mode as outlined in Book “Reference”, Chapter 12 “The boot loader GRUB 2”, Section 12.5 “Rescue mode”, Entering rescue mode.

21.3.2 Valid user name and password not accepted Edit source

This is by far the most common problem users encounter, because there are many reasons this can occur. Depending on whether you use local user management and authentication or network authentication, login failures occur for different reasons.

Local user management can fail for the following reasons:

  • The user may have entered the wrong password.

  • The user's home directory containing the desktop configuration files is corrupted or write protected.

  • There may be problems with the X Window System authenticating this particular user, especially if the user's home directory has been used with another Linux distribution before installing the current one.

To locate the reason for a local login failure, proceed as follows:

  1. Check whether the user remembered their password correctly before you start debugging the whole authentication mechanism. If the user may have not have remembered their password correctly, use the YaST User Management module to change the user's password. Pay attention to the Caps Lock key and unlock it, if necessary.

  2. Log in as root and check the system journal with journalctl -e for error messages of the login process and of PAM.

  3. Try to log in from a console (using CtrlAltF1). If this is successful, the blame cannot be put on PAM, because it is possible to authenticate this user on this machine. Try to locate any problems with the X Window System or the GNOME desktop. For more information, refer to Section 21.3.4, “GNOME desktop has issues”.

  4. If the user's home directory has been used with another Linux distribution, remove the Xauthority file in the user's home. Use a console login via CtrlAltF1 and run rm .Xauthority as this user. This should eliminate X authentication problems for this user. Try graphical login again.

  5. If the desktop could not start because of corrupt configuration files, proceed with Section 21.3.4, “GNOME desktop has issues”.

In the following, common reasons a network authentication for a particular user may fail on a specific machine are listed:

  • The user may have entered the wrong password.

  • The user name exists in the machine's local authentication files and is also provided by a network authentication system, causing conflicts.

  • The home directory exists but is corrupt or unavailable. Perhaps it is write protected or is on a server that is inaccessible at the moment.

  • The user does not have permission to log in to that particular host in the authentication system.

  • The machine has changed host names, for whatever reason, and the user does not have permission to log in to that host.

  • The machine cannot reach the authentication server or directory server that contains that user's information.

  • There may be problems with the X Window System authenticating this particular user, especially if the user's home has been used with another Linux distribution before installing the current one.

To locate the cause of the login failures with network authentication, proceed as follows:

  1. Check whether the user remembered their password correctly before you start debugging the whole authentication mechanism.

  2. Determine the directory server which the machine relies on for authentication and make sure that it is up and running and properly communicating with the other machines.

  3. Determine that the user's user name and password work on other machines to make sure that their authentication data exists and is properly distributed.

  4. See if another user can log in to the misbehaving machine. If another user can log in without difficulty or if root can log in, log in and examine the system journal with the journalctl -e > file. Locate the time stamps that correspond to the login attempts and determine if PAM has produced any error messages.

  5. Try to log in from a console (using CtrlAltF1). If this is successful, the problem is not with PAM or the directory server on which the user's home is hosted, because it is possible to authenticate this user on this machine. Try to locate any problems with the X Window System or the GNOME desktop. For more information, refer to Section 21.3.4, “GNOME desktop has issues”.

  6. If the user's home directory has been used with another Linux distribution, remove the Xauthority file in the user's home. Use a console login via CtrlAltF1 and run rm .Xauthority as this user. This should eliminate X authentication problems for this user. Try graphical login again.

  7. If the desktop could not start because of corrupt configuration files, proceed with Section 21.3.4, “GNOME desktop has issues”.

21.3.3 Login to encrypted home partition fails Edit source

It is recommended to use an encrypted home partition for laptops. If you cannot log in to your laptop, the reason might be that your partition could not be unlocked.

During the boot time, you need to enter the passphrase to unlock your encrypted partition. If you do not enter it, the boot process continues, leaving the partition locked.

To unlock your encrypted partition, proceed as follows:

  1. Switch to the text console with CtrlAltF1.

  2. Become root.

  3. Restart the unlocking process again with:

    # systemctl restart home.mount
  4. Enter your passphrase to unlock your encrypted partition.

  5. Exit the text console and switch back to the login screen with AltF7.

  6. Log in as usual.

21.3.4 GNOME desktop has issues Edit source

If you are experiencing issues with the GNOME desktop, there are several ways to troubleshoot the misbehaving graphical desktop environment. The recommended procedure described below offers the safest option to fix a broken GNOME desktop.

Procedure 21.1: Troubleshooting GNOME
  1. Launch YaST and switch to Security and Users.

  2. Open the User and Group Management dialog and click Add.

  3. Fill out the required fields and click OK to create a new user.

  4. Log out and log in as the new user. This gives you a fresh GNOME environment.

  5. Copy individual subdirectories from the ~/.local/ and ~/.config/ directories of the old user account to the respective directories of the new user account.

    Log out and log in again as the new user after every copy operation to check whether GNOME still works correctly.

  6. Repeat the previous step until you find the configuration file that breaks GNOME.

  7. Log in as the old user, and move the offending configuration file to a different location. Log out and log in again as the old user.

  8. Delete the previously created user.

21.4 Network problems Edit source

Many problems of your system may be network-related, although the symptoms look different. For example, the reason for a system not allowing users to log in may be a network problem. This section introduces a simple checklist you can apply to identify the cause of any network problem encountered.

Procedure 21.2: How to identify network problems

When checking the network connection of your machine, proceed as follows:

  1. If you use an Ethernet connection, check the hardware first. Make sure that your network cable is properly plugged into your computer and router (or hub, etc.). The control lights next to your Ethernet connector are normally both be active.

    If the connection fails, check whether your network cable works with another machine. If it does, your network card causes the failure. If hubs or switches are included in your network setup, they may be faulty, as well.

  2. If using a wireless connection, check whether the wireless link can be established by other machines. If not, contact the wireless network's administrator.

  3. When you have checked your basic network connectivity, try to find out which service is not responding. Gather the address information of all network servers needed in your setup. Either look them up in the appropriate YaST module or ask your system administrator. The following list gives typical network servers involved in a setup together with the symptoms of an outage.

    DNS (name service)

    A broken or malfunctioning name service affects the network's functionality in many ways. If the local machine relies on any network servers for authentication and these servers cannot be found because of name resolution issues, users would not even be able to log in. Machines in the network managed by a broken name server would not be able to see each other and communicate.

    NTP (time service)

    A malfunctioning or broken NTP service could affect Kerberos authentication and X server functionality.

    NFS (file service)

    If any application needs data stored in an NFS mounted directory, it cannot start or function properly if this service was down or misconfigured. In the worst case scenario, a user's personal desktop configuration would not come up if their home directory containing the .gconf subdirectory could not be found because of a faulty NFS server.

    Samba (file service)

    If any application needs data stored in a directory on a faulty Samba server, it cannot start or function properly.

    NIS (user management)

    If your openSUSE Leap system relies on a faulty NIS server to provide the user data, users cannot log in to this machine.

    LDAP (user management)

    If your openSUSE Leap system relies on a faulty LDAP server to provide the user data, users cannot log in to this machine.

    Kerberos (authentication)

    Authentication does not work and login to any machine fails.

    CUPS (network printing)

    Users cannot print.

  4. Check whether the network servers are running and whether your network setup allows you to establish a connection:

    Important
    Important: Limitations

    The debugging procedure described below only applies to a simple network server/client setup that does not involve any internal routing. It assumes both server and client are members of the same subnet without the need for additional routing.

    1. Use ping IP_ADDRESS/HOSTNAME (replace with the host name or IP address of the server) to check whether each one of them is up and responding to the network. If this command is successful, it tells you that the host you were looking for is up and running and that the name service for your network is configured correctly.

      If ping fails with destination host unreachable, either your system or the desired server is not properly configured or down. Check whether your system is reachable by running ping IP address or YOUR_HOSTNAME from another machine. If you can reach your machine from another machine, it is the server that is not running or not configured correctly.

      If ping fails with unknown host, the name service is not configured correctly or the host name used was incorrect. For further checks on this matter, refer to Step 4.b. If ping still fails, either your network card is not configured correctly or your network hardware is faulty.

    2. Use host HOSTNAME to check whether the host name of the server you are trying to connect to is properly translated into an IP address and vice versa. If this command returns the IP address of this host, the name service is up and running. If the host command fails, check all network configuration files relating to name and address resolution on your host:

      /var/run/netconfig/resolv.conf

      This file is used to keep track of the name server and domain you are currently using. It is a symbolic link to /run/netconfig/resolv.conf and is usually automatically adjusted by YaST or DHCP. Make sure that this file has the following structure and all network addresses and domain names are correct:

      search FULLY_QUALIFIED_DOMAIN_NAME
      nameserver IPADDRESS_OF_NAMESERVER

      This file can contain more than one name server address, but at least one of them must be correct to provide name resolution to your host. If needed, adjust this file using the YaST Network Settings module (Hostname/DNS tab).

      If your network connection is handled via DHCP, enable DHCP to change host name and name service information by selecting Set Hostname via DHCP (can be set globally for any interface or per interface) and Update Name Servers and Search List via DHCP in the YaST Network Settings module (Hostname/DNS tab).

      /etc/nsswitch.conf

      This file tells Linux where to look for name service information. It should look like this:

       ...
      hosts: files dns
      networks: files dns
      ...

      The dns entry is vital. It tells Linux to use an external name server. Normally, these entries are automatically managed by YaST, but it would be prudent to check.

      If all the relevant entries on the host are correct, let your system administrator check the DNS server configuration for the correct zone information. For detailed information about DNS, refer to Book “Reference”, Chapter 19 “The domain name system”. If you have made sure that the DNS configuration of your host and the DNS server are correct, proceed with checking the configuration of your network and network device.

    3. If your system cannot establish a connection to a network server and you have excluded name service problems from the list of possible culprits, check the configuration of your network card.

      Use the command ip addr show NETWORK_DEVICE to check whether this device was properly configured. Make sure that the inet address with the netmask (/MASK) is configured correctly. An error in the IP address or a missing bit in your network mask would render your network configuration unusable. If necessary, perform this check on the server as well.

    4. If the name service and network hardware are properly configured and running, but certain external network connections still get long timeouts or fail entirely, use traceroute FULLY_QUALIFIED_DOMAIN_NAME (executed as root) to track the network route these requests are taking. This command lists any gateway (hop) that a request from your machine passes on its way to its destination. It lists the response time of each hop and whether this hop is reachable. Use a combination of traceroute and ping to track down the culprit and let the administrators know.

When you have identified the cause of your network trouble, you can resolve it yourself (if the problem is located on your machine) or let the system administrators of your network know about your findings so they can reconfigure the services or repair the necessary systems.

21.4.1 NetworkManager problems Edit source

If you have a problem with network connectivity, narrow it down as described in Procedure 21.2, “How to identify network problems”. If NetworkManager looks suspicious, proceed as follows to get logs providing hints on why NetworkManager fails:

  1. Open a shell and log in as root.

  2. Restart the NetworkManager:

    > sudo systemctl restart NetworkManager
  3. Open a Web page, for example, https://www.opensuse.org as normal user to see, if you can connect.

  4. Collect any information about the state of NetworkManager in /var/log/NetworkManager.

For more information about NetworkManager, refer to Book “Reference”, Chapter 28 “Using NetworkManager”.

21.5 Data problems Edit source

Data problems are when the machine may or may not boot properly but, in either case, it is clear that there is data corruption on the system and that the system needs to be recovered. These situations call for a backup of your critical data, enabling you to recover the system state from before your system failed.

21.5.1 Managing partition images Edit source

Sometimes you need to perform a backup from an entire partition or even hard disk. Linux comes with the dd tool which can create an exact copy of your disk. Combined with gzip you save space.

Procedure 21.3: Backing up and restoring hard disks
  1. Start a Shell as user root.

  2. Select your source device. Typically this is something like /dev/sda (labeled as SOURCE).

  3. Decide where you want to store your image (labeled as BACKUP_PATH). It must be different from your source device. In other words: if you make a backup from /dev/sda, your image file must not to be stored under /dev/sda.

  4. Run the commands to create a compressed image file:

    # dd if=/dev/SOURCE | gzip > /BACKUP_PATH/image.gz
  5. Restore the hard disk with the following commands:

    # gzip -dc /BACKUP_PATH/image.gz | dd of=/dev/SOURCE

If you only need to back up a partition, replace the SOURCE placeholder with your respective partition. In this case, your image file can lie on the same hard disk, but on a different partition.

21.5.2 Using the rescue system Edit source

There are several reasons a system could fail to come up and run properly. A corrupted file system following a system crash, corrupted configuration files, or a corrupted boot loader configuration are the most common ones.

To help you to resolve these situations, openSUSE Leap contains a rescue system that you can boot. The rescue system is a small Linux system that can be loaded into a RAM disk and mounted as root file system, allowing you to access your Linux partitions from the outside. Using the rescue system, you can recover or modify any important aspect of your system.

  • Manipulate any type of configuration file.

  • Check the file system for defects and start automatic repair processes.

  • Access the installed system in a change root environment.

  • Check, modify, and re-install the boot loader configuration.

  • Recover from a badly installed device driver or unusable kernel.

  • Resize partitions using the parted command. Find more information about this tool at the GNU Parted Web site https://www.gnu.org/software/parted/parted.html.

The rescue system can be loaded from various sources and locations. The simplest option is to boot the rescue system from the original installation medium.

  1. Insert the installation medium into your DVD drive.

  2. Reboot the system.

  3. At the boot screen, press F4 and choose DVD-ROM. Then choose Rescue System from the main menu.

  4. Enter root at the Rescue: prompt. A password is not required.

If your hardware setup does not include a DVD drive, you can boot the rescue system from a network source. The following example applies to a remote boot scenario—if using another boot medium, such as a DVD, modify the info file accordingly and boot as you would for a normal installation.

  1. Enter the configuration of your PXE boot setup and add the lines install=PROTOCOL://INSTSOURCE and rescue=1. If you need to start the repair system, use repair=1 instead. As with a normal installation, PROTOCOL stands for any of the supported network protocols (NFS, HTTP, FTP, etc.) and INSTSOURCE for the path to your network installation source.

  2. Boot the system using Wake on LAN.

  3. Enter root at the Rescue: prompt. A password is not required.

When you have entered the rescue system, you can use the virtual consoles that can be reached with AltF1 to AltF6.

A shell and other useful utilities, such as the mount program, are available in the /bin directory. The /sbin directory contains important file and network utilities for reviewing and repairing the file system. This directory also contains the most important binaries for system maintenance, such as fdisk, mkfs, mkswap, mount, and shutdown, ip and ss for maintaining the network. The directory /usr/bin contains the vi editor, find, less, and SSH.

To see the system messages, either use the command dmesg or view the system log with journalctl.

21.5.2.1 Checking and manipulating configuration files Edit source

As an example for a configuration that might be fixed using the rescue system, imagine you have a broken configuration file that prevents the system from booting properly. You can fix this using the rescue system.

To manipulate a configuration file, proceed as follows:

  1. Start the rescue system using one of the methods described above.

  2. To mount a root file system located under /dev/sda6 to the rescue system, use the following command:

    > sudo mount /dev/sda6 /mnt

    All directories of the system are now located under /mnt

  3. Change the directory to the mounted root file system:

    > sudo cd /mnt
  4. Open the problematic configuration file in the vi editor. Adjust and save the configuration.

  5. Unmount the root file system from the rescue system:

    > sudo umount /mnt
  6. Reboot the machine.

21.5.2.2 Repairing and checking file systems Edit source

Generally, file systems cannot be repaired on a running system. If you encounter serious problems, you may not even be able to mount your root file system and the system boot may end with a kernel panic. In this case, the only way is to repair the system from the outside. The system contains the fsck utility to check and repair multiple file system types, such as ext2, ext3, ext4, msdos, and vfat. Use the -t option to specify which file system to check.

The following command checks all ext4 file systems found in the /etc/fstab specification:

> sudo fsck -t ext4 -A
Tip
Tip

For Btrfs, you can use the btrfs check command found in the btrfsprogs package.

Find topics about the Btrfs file system in the following places:

21.5.2.3 Accessing the installed system Edit source

If you need to access the installed system from the rescue system, you need to do this in a change root environment. For example, to modify the boot loader configuration, or to execute a hardware configuration utility.

To set up a change root environment based on the installed system, proceed as follows:

  1. Tip
    Tip: Import LVM volume groups

    If you are using an LVM setup (refer to Book “Reference”, Chapter 5 “Expert Partitioner”, Section 5.3 “LVM configuration” for more general details), import all existing volume groups to be able to find and mount the device(s):

    rootvgimport -a

    Run lsblk to check which node corresponds to the root partition. It is /dev/sda2 in our example:

    > lsblk
    NAME        MAJ:MIN RM   SIZE RO TYPE  MOUNTPOINT
    sda           8:0    0 149,1G  0 disk
    ├─sda1        8:1    0     2G  0 part  [SWAP]
    ├─sda2        8:2    0    20G  0 part  /
    └─sda3        8:3    0   127G  0 part
      └─cr_home 254:0    0   127G  0 crypt /home
  2. Mount the root partition from the installed system:

    > sudo mount /dev/sda2 /mnt
  3. Mount /proc, /dev, and /sys partitions:

    > sudo mount -t proc none /mnt/proc
    > sudo mount --rbind /dev /mnt/dev
    > sudo mount --rbind /sys /mnt/sys
  4. Now you can change root into the new environment, keeping the bash shell:

    > chroot /mnt /bin/bash
  5. Finally, mount the remaining partitions from the installed system:

    > mount -a
  6. Now you have access to the installed system. Before rebooting the system, unmount the partitions with umount -a and leave the change root environment with exit.

Warning
Warning: Limitations

Although you have full access to the files and applications of the installed system, there are some limitations. The kernel that is running is the one that was booted with the rescue system, not with the change root environment. It only supports essential hardware and it is not possible to add kernel modules from the installed system unless the kernel versions are identical. Always check the version of the currently running (rescue) kernel with uname -r and then find out if a matching subdirectory exists in the /lib/modules directory in the change root environment. If yes, you can use the installed modules, otherwise you need to supply their correct versions on other media, such as a flash disk. Most often the rescue kernel version differs from the installed one — then you cannot simply access a sound card, for example. It is also not possible to start a graphical user interface.

Also note that you leave the change root environment when you switch the console with AltF1 to AltF6.

21.5.2.4 Modifying and re-installing the boot loader Edit source

Sometimes a system cannot boot because the boot loader configuration is corrupted. The start-up routines cannot, for example, translate physical drives to the actual locations in the Linux file system without a working boot loader.

To check the boot loader configuration and re-install the boot loader, proceed as follows:

  1. Perform the necessary steps to access the installed system as described in Section 21.5.2.3, “Accessing the installed system”.

  2. Check that the GRUB 2 boot loader is installed on the system. If not, install the package grub2 and run

    > sudo grub2-install /dev/sda
  3. Check whether the following files are correctly configured according to the GRUB 2 configuration principles outlined in Book “Reference”, Chapter 12 “The boot loader GRUB 2” and apply fixes if necessary.

    • /etc/default/grub

    • /boot/grub2/device.map

    • /boot/grub2/grub.cfg (this file is generated, do not edit)

    • /etc/sysconfig/bootloader

  4. Re-install the boot loader using the following command sequence:

    > sudo grub2-mkconfig -o /boot/grub2/grub.cfg
  5. Unmount the partitions, log out of the change root environment, and reboot the system:

    > umount -a
    exit
    reboot

21.5.2.5 Fixing kernel installation Edit source

A kernel update may introduce a new bug which can impact the operation of your system. For example a driver for a piece of hardware in your system may be faulty, which prevents you from accessing and using it. In this case, revert to the last working kernel (if available on the system) or install the original kernel from the installation media.

Tip
Tip: How to keep last kernels after update

To prevent failures to boot after a faulty kernel update, use the kernel multiversion feature and tell libzypp which kernels you want to keep after the update.

For example to always keep the last two kernels and the currently running one, add

multiversion.kernels = latest,latest-1,running

to the /etc/zypp/zypp.conf file. See Book “Reference”, Chapter 6 “Installing multiple kernel versions” for more information.

A similar case is when you need to re-install or update a broken driver for a device not supported by openSUSE Leap. For example when a hardware vendor uses a specific device, such as a hardware RAID controller, which needs a binary driver to be recognized by the operating system. The vendor typically releases a Driver Update Disk (DUD) with the fixed or updated version of the required driver.

In both cases you need to access the installed system in the rescue mode and fix the kernel related problem, otherwise the system may fail to boot correctly:

  1. Boot from the openSUSE Leap installation media.

  2. If you are recovering after a faulty kernel update, skip this step. If you need to use a driver update disk (DUD), press F6 to load the driver update after the boot menu appears, and choose the path or URL to the driver update and confirm with Yes.

  3. Choose Rescue System from the boot menu and press Enter. If you chose to use DUD, you will be asked to specify where the driver update is stored.

  4. Enter root at the Rescue: prompt. A password is not required.

  5. Manually mount the target system and change root into the new environment. For more information, see Section 21.5.2.3, “Accessing the installed system”.

  6. If using DUD, install/re-install/update the faulty device driver package. Always make sure the installed kernel version exactly matches the version of the driver you are installing.

    If fixing faulty kernel update installation, you can install the original kernel from the installation media with the following procedure.

    1. Identify your DVD device with hwinfo --cdrom and mount it with mount /dev/sr0 /mnt.

    2. Navigate to the directory where your kernel files are stored on the DVD, for example cd /mnt/suse/x86_64/.

    3. Install required kernel-*, kernel-*-base, and kernel-*-extra packages of your flavor with the rpm -i command.

  7. Update configuration files and reinitialize the boot loader if needed. For more information, see Section 21.5.2.4, “Modifying and re-installing the boot loader”.

  8. Remove any bootable media from the system drive and reboot.

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