If your network setup supports OpenSLP and your network installation source has been configured to announce itself via SLP (described in Section 2.2, “Setting Up the Server Holding the Installation Sources”), boot the system, press F4 in the boot screen and select SLP from the menu.

The installation program configures the network connection with DHCP and retrieves the location of the network installation source from the OpenSLP server. If the automatic DHCP network configuration fails, you are prompted to enter the appropriate parameters manually. The installation then proceeds as described below with the exception of the network configuration step that is needed prior to adding additional repositories. This step is not needed as the network is already configured and active at this point.

If your network setup does not support OpenSLP for the retrieval of network installation sources, boot the system and press F4 in the boot screen to select the desired network protocol (NFS, HTTP, FTP, or SMB/CIFS). Provide the server's address and the path to the installation media.

The installation program automatically configures the network connection with DHCP. If this configuration fails, you are prompted to enter the appropriate parameters manually. The installation retrieves the installation data from the source specified. The installation then proceeds as described below with the exception of the network configuration step needed prior to adding additional repositories. This step is not needed as the network is already configured and active at this point.

openSUSE 12.1 Installer is a Microsoft Windows application that prepares your computer to directly boot into the openSUSE installation without having to adjust BIOS settings. It is only available on DVD media. To use the installer, insert the openSUSE media under Windows. The openSUSE 12.1 Installer setup automatically starts (if not, run openSUSE11_2_LOCAL.exe from the DVD). Choose a language for the installation and follow the instructions on the screen. The language you choose here is also preconfigured to be used for the openSUSE installation.

On the next reboot, the Microsoft Windows boot loader launches. Choose openSUSE 12.1 Installer to start the openSUSE installation. In order to proceed with the installation, you will be prompted to insert the installation media. The installation proceeds as described below. When Microsoft Windows is booted again, openSUSE 12.1 Installer is automatically uninstalled.

Installing openSUSE alongside Microsoft Windows

openSUSE can easily be installed alongside Microsoft Windows. Carry out the installation as described below—an existing Windows installation will automatically be detected and a dual boot option will be installed. If Windows covers the whole installation disk, the installation routine will make a proposal to shrink an existing Windows partition in order to make room for the openSUSE. Please read Section 1.10.1.1, “Resizing a Windows Partition” prior to the installation for detailed information.

Add-on products can be installed either from a local source (CD, DVD, or directory) or from a network source (HTTP, FTP, NFS, CIFS,...). When installing from a network source, you need to configure the network first (unless you are performing a network installation— in this case the existing network configuration is used). Choose Yes, Run the Network Setup and proceed as described in Section 1.7.1.1, “Network Setup”. If the add-on product is available locally, select No, Skip the Network Setup.

Click Next and specify the product source. Source types available are CD, DVD, Hard Disk, USB Mass Storage, a Local Directory or a Local ISO Image (if no network was configured). If the add-on product is available on removable media, the system automatically mounts the media and reads its contents. If the add-on product is available on hard disk, choose Hard Disk to install from an unmounted hard drive, or Local Directory/Local ISO Image to install from the local file system. Add-on products may be delivered as a repository or as a set of rpm files. In the latter case, check Plain RPM Directory. Whenever a network is available, you can choose from additional remote sources such as HTTP, SLP, FTP, etc. It is also possible to specify a URL directly.

Check Download Repository Description Files to download the files describing the repository now. If unchecked, they will be downloaded once the installation starts. Proceed with Next and insert a CD or DVD if required. Depending on the product's content it may be necessary to accept additional license agreements.

It is also possible to configure add-on products later. Using add-on products on the installed system is described in Chapter 8, Installing Add-On Products (↑Start-Up).

If your machine contains more than one hard disk and you want to restrict the partitioning proposal to just one disk, choose Create Partition Setup and then select a specific disk from the list. If the chosen hard disk does not contain any partitions yet, the whole hard disk will be used for the proposal. Otherwise, you can choose which existing partition(s) to utilize. To add a separate partition for you personal data check Propose a Separate Home Partition. Instead of the default partition-based proposal, it is possible to Create an LVM Based Proposal. Choose two times Next to proceed to the next step.

1.10.1.1. Resizing a Windows Partition¶

If the selected hard disk only contains a Windows FAT or NTFS partition, YaST offers to delete or shrink this partition. If you select Delete Windows Completely, the Windows partition is marked for deletion and the space is used for the installation of openSUSE.

	Deleting Windows
If you delete Windows, all data will be lost beyond recovery as soon as the formatting starts.

To Shrink the Windows Partition, you need to interrupt the installation and boot Windows to prepare the partition before shrinking it. For all Windows file systems, proceed as follows:

1. Deactivate a Virtual Memory file, if there is one.

2. Run scandisk.

3. Run defrag.

After these preparations, restart the openSUSE installation. When you turn to the partitioning setup, proceed as before and select Shrink Windows Partition. After a quick check of the partition, the dialog for resizing the Windows partition opens.

The bar graph shows how much disk space is currently occupied by Windows and how much space is still available. To change the proposed settings use the slider or the input fields to adjust the partition sizing.

Figure 1.7. Resizing the Windows Partition¶

If you leave this dialog by selecting Next, the settings are stored and you are returned to the previous dialog. The actual resizing takes place later, before the hard disk is formatted.

	Writing on NTFS Partitions
By default, the Windows uses the NTFS file system. openSUSE includes read and write access to the NTFS file system, but this feature has a few limitations. This means that you cannot read or write encrypted or compressed files. Furthermore, the Windows file permissions are not honored at the moment. See http://en.opensuse.org/SDB:NTFS for more information.

Set up your own partitioning scheme by selecting Create Partition Setup and then Custom Partitioning. The Expert Partitioner opens, displaying the current partition setup. Expand the Hard Disks in the System View pane by clicking on the +, then click on one of the listed hard disks. Now you can Add, Edit, Resize, or Delete partitions. For more information about custom partitioning and configuring advanced features, refer to Section 3.1, “Using the YaST Partitioner”

Click Change in the Create User dialog to set up network authentication or, if present, import users from a previous installation. Also change the password encryption type in this dialog.

You can also add additional user accounts or change the user authentication method in the installed system. For detailed information about user management, see Chapter 10, Managing Users with YaST (↑Start-Up).

The default authentication method is Local (/etc/passwd). If a former version of openSUSE or another system using /etc/passwd is detected, you may import local users. To do so, check Read User Data from a Previous Installation and click Choose. In the next dialog, select the users to import and finish with OK.

Access to the following network authentication services can be configured:

Along with user administration via LDAP and NIS, you can use Kerberos authentication. To use it, select Set Up Kerberos Authentication. For more information on Kerberos, refer to Chapter 6, Network Authentication with Kerberos (↑Security Guide).

If you have not chosen Use this Password for the System Administrator in the previous step, you will be prompted to enter a Password for the System Administrator root. Otherwise this configuration step is skipped.

root is the name of the superuser, or the administrator of the system. Unlike regular users (who may or may not have permission to access certain areas or execute certain commands on the system), root has unlimited access to change the system configuration, install programs, and set up new hardware. If users forget their passwords or have other problems with the system, root can help. The root account should only be used for system administration, maintenance, and repair. Logging in as root for daily work is rather risky: a single mistake could lead to irretrievable loss of system files.

For verification purposes, the password for root must be entered twice. Do not forget the root password. Once entered, this password cannot be retrieved.

The root can be changed any time later in the installed system. To do so run YaST and start Security and Users+User and Group Management.

	The root User
The user root has all the permissions needed to make changes to the system. To carry out such tasks, the root password is required. You cannot carry out any administrative tasks without this password.

Review and, if necessary, change the partition setup you configured earlier. Modifying the partition setup opens the Expert Partitioner described in Section 3.1, “Using the YaST Partitioner”.

YaST 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 will be booted by default. Normally, you can leave these settings unchanged. If you need a custom setup, modify the proposal for your system. For information, see Section 6.2, “Configuring the Boot Loader with YaST”. The boot method should only be changed by experienced users.

openSUSE contains a number of software patterns for various application purposes. Click Software to start the pattern selection and modify the installation scope according to your needs. Select your pattern from the list and see a pattern description in the right part of the window. Each pattern contains a number of software packages needed for specific functions (e.g. Multimedia or Office software). For a more detailed selection based on software packages to install, select Details to switch to the YaST Software Manager.

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 5, Installing or Removing Software (↑Start-Up).

Figure 1.10. Software Selection and System Tasks

Here you can change the system Language and Keyboard Layout you defined in the first step of the installation. It is also possible to add additional languages. To adjust the system language settings, select Language. Select a language from the list. The primary language is used as the system language. You can also adapt keyboard layout and time zone to the primary language if the current settings differ. Details lets you modify language settings for the user root, set UTF-8 support, or further specify the language (e.g. select South African English).

Choose secondary languages to be able to switch to one of these languages at any time without having to install additional packages. For more information, see Chapter 11, Changing Language and Country Settings with YaST (↑Start-Up).

To change the keyboard layout, select Keyboard Layout. By default, the layout corresponds to the language chosen for installation. Select the keyboard layout from the list. Use the Test field at the bottom of the dialog to check if you can enter special characters of that layout correctly. Options to fine-tune various settings are available under Expert Mode. When finished, click Accept to return to the installation summary.

Adjust time zone and clock settings here. Provided a network is configured, you can also set up a Network Time Protocol (NTP) client that automatically synchronizes your computer with a time server. This is the same configuration as shown earlier in Section 1.8, “Clock and Time Zone”.

Change the current User settings and change or set the Root Password here. This is the same configuration as shown earlier in Section 1.11, “Create New User”.

openSUSE can boot to different runlevels. Normally, there should be no need to change anything here, but if necessary set the default runlevel with this dialog.

This dialog presents all the hardware information YaST could obtain about your computer. When called, the hardware detection routine 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 floppy. Advanced users can also change the PCI ID setup and Kernel Settings by choosing Kernel Settings.

Installing from images considerably speeds up the installation. Images contain compressed snapshots of installed systems matching your selection of patterns. Packages not contained in the images deployed will be installed conventionally.

Unless your custom software selection does not match any of the available images, this feature is Enabled by default. In case of problems, Disable it for debugging purposes.

By default SuSEFirewall2 is enabled on all configured network interfaces. To globally disable the firewall for this computer, click on Disable. If the firewall is enabled, you may Open the SSH port in order to allow remote connections via secure shell.

Having rebooted, the system starts the Automatic Configuration. This routine attempts to configure your network and Internet access and sets up your hardware. This process does not need any interaction. You can change the settings made by Automatic Configuration at any time on the installed system with YaST. Continue with Section 1.15, “Graphical Login”.

Having rebooted, the system starts the manual configuration. If the configuration fails at one of the steps of this stage, it restarts and continues from the last successful step.

1.14.2.2. Network Configuration¶

If you are installing openSUSE on a laptop computer, Interfaces Controlled by NetworkManager is enabled. NetworkManager is a tool that enables automatic connection with minimal user intervention. It is ideal for WLAN and mobile computing. If you want to use the traditional method without NetworkManager, click Disable NetworkManager. Find detailed information about NetworkManager in Chapter 21, Using NetworkManager. If you are installing openSUSE on any other type of machine, the traditional method without NetworkManager is selected by default. This configuration step also lets you configure the network devices of your system and make security settings, for example, for a firewall or proxy.

The network can also be configured after the system installation has been completed. If you skip it now, your system is left offline unable to retrieve any available updates. To configure your network connection later, select Skip Configuration and click Next.

The following network settings can be configured in this step:

General Network Settings

Enable or disable the use of NetworkManager as described above. Also change the IPv6 support here. By default the IPv6 support is enabled. To disable it, click Disable IPv6. For more information about IPv6, see Section 9.2, “IPv6—The Next Generation Internet”.

Firewall

By default SuSEFirewall2 is enabled on all configured network interfaces. To globally disable the firewall for this computer, click on Disable. If the firewall is enabled, you may Open the SSH port in order to allow remote connections via secure shell. To open the detailed firewall configuration dialog, click on Firewall. See Section “Configuring the Firewall with YaST” (Chapter 13, Masquerading and Firewalls, ↑Security Guide) for detailed information.

Network Interfaces

All network cards detected by YaST are listed here. If you have already set up a network connection during the installation (as described in Section 1.7.1.1, “Network Setup”) the card used for this connection is listed as Configured. A click on Network Interfaces opens the Network Settings dialog, where you can change existing configurations, set up networks cards not configured yet, or add and configure additional cards.

DSL Connections, ISDN Adapters, and Modems

If your computer is equipped with an internal DSL modem, an internal ADSL Fritz Card, an ISDN card or a modem, clicking on the respective headline opens the configuration dialog.

VNC Remote Administration

To enable remote administration of your machine via VNC, click VNC Remote Administration. Choose Allow Remote Administration in the following dialog and adjust your firewall settings accordingly.

Proxy

If you have a proxy server controlling the Internet access in your network, configure the proxy URLs and authentication details in this dialog.

	Resetting the Network Configuration to the Default Values
Reset the network settings to the original proposed values by clicking Change+Reset to Defaults. This discards any changes made.

1.14.2.2.1. Test Internet Connection¶

After having configured a network connection, you can test it. For this purpose, YaST establishes a connection to the openSUSE server and downloads the latest release notes. Read them at the end of the installation process. A successful test is also a prerequisite for the automatic addition of the default repositories and for updating online.

If you have multiple network interfaces, verify that the desired card is used to connect to the Internet. If not, click Change Device.

To start the test, select Yes, Test Connection to the Internet and click Next. In the following dialog, view the progress of the test and the results. Detailed information about the test process is available via View Logs. If the test fails, click Back to return to the network configuration to correct your entries.

Proceed with Next. If the test was successful, the official software repositories for openSUSE and the update repository will be configured. Downloading the repository data for the first time may take some time.

If you do not want to test the connection at this point, select No, Skip This Test then Next. This also skips downloading the release notes, and updating online. These steps can be performed any time after the system has been initially configured.

1.14.2.3. Online Update¶

If an Internet connection has been established, and updates are available, select whether to perform a YaST online update. If there are any patched packages available on the servers, download and install them now to fix known bugs or security issues. For detailed instructions see Chapter 6, YaST Online Update (↑Start-Up). Directives on how to perform an online update in the installed system are available at Section “Keeping the System Up-to-date” (Chapter 5, Installing or Removing Software, ↑Start-Up) or Chapter 6, YaST Online Update (↑Start-Up). This step is skipped if no updates are available or no Internet connection has been established. Patches fixing security issues and recommended patches applying to your installation are automatically preselected. Click Accept to install them and Next to proceed with the system configuration.

	Downloading Software Updates
The download of updates might take quite some time, depending on the bandwidth of the Internet connection and the size of the update files. In case the patch system itself is updated, the online update will restart and download more patches after the restart. If the kernel was updated, the system will reboot before completing the configuration.

1.14.2.6. Hardware Configuration¶

At the end of the installation, YaST opens a dialog for the configuration of Graphics Cards Printer . Click the individual components to start the hardware configuration. For the most part, YaST detects and configures the devices automatically.

You can skip any peripheral devices and configure them later, as described in Chapter 13, Setting Up Hardware Components with YaST (↑Start-Up). To skip the configuration, select Skip Configuration and click Next.

	Resetting Hardware Configuration to the Default Values
You can cancel any changes to the hardware configuration by clicking Change+Reset to Defaults. YaST then shows the original proposal again.

This type of installation still requires some degree of physical access to the target system to boot for installation. The installation itself is entirely controlled by a remote workstation using VNC to connect to the installation program. User interaction is required as with the manual installation in Chapter 1, Installation with YaST.

For this type of installation, make sure that the following requirements are met:

This type of installation still requires some degree of physical access to the target system to boot for installation. The network configuration is made with DHCP. The installation itself is entirely controlled from a remote workstation using VNC to connect to the installer, but still requires user interaction for the actual configuration efforts.

For this type of installation, make sure that the following requirements are met:

This type of installation is completely hands-off. The target machine is started and booted remotely. User interaction is only needed for the actual installation. This approach is suitable for cross-site deployments.

To perform this type of installation, make sure that the following requirements are met:

This type of installation still requires some degree of physical access to the target system to boot for installation and to determine the IP address of the installation target. The installation itself is entirely controlled from a remote workstation using SSH to connect to the installer. User interaction is required as with the regular installation described in Chapter 1, Installation with YaST.

For this type of installation, make sure that the following requirements are met:

This type of installation still requires some degree of physical access to the target system to boot for installation and determine the IP address of the installation target. The installation itself is entirely controlled from a remote workstation using VNC to connect to the installer, but still requires user interaction for the actual configuration efforts.

For this type of installation, make sure that the following requirements are met:

This type of installation is completely hands-off. The target machine is started and booted remotely.

To perform this type of installation, make sure that the following requirements are met:

YaST offers a graphical tool for creating network repositories. It supports HTTP, FTP, and NFS network installation servers.

To deactivate a repository, select the repository to remove then select Delete. The installation data are removed from the system. To deactivate the network service, use the respective YaST module.

If your installation server needs to provide the installation data for more than one product of the product version, start the YaST installation server module and select Add in the overview of existing repositories to configure the new repository.

Setting up an NFS source for installation is basically done in two steps. In the first step, create the directory structure holding the installation data and copy the installation media over to this structure. Second, export the directory holding the installation data to the network.

For more information about OpenSLP, refer to the package documentation located under /usr/share/doc/packages/openslp/ or refer to Chapter 10, SLP Services in the Network. More Information about NFS, refer to Chapter 14, Sharing File Systems with NFS.

Creating an FTP repository is very similar to creating an NFS repository. An FTP repository can be announced over the network using OpenSLP as well.

	Configuring an FTP Server with YaST
If you prefer using YaST over manually configuring the FTP installation server, refer to Chapter 17, Setting up an FTP server with YaST for more information on how to use the YaST FTP server module.

Creating an HTTP repository is very similar to creating an NFS repository. An HTTP repository can be announced over the network using OpenSLP as well.

Using SMB, you can import the installation sources from a Microsoft Windows server and start your Linux deployment even with no Linux machine around.

To use a SMB mounted share as a repository, proceed as follows:

Instead of copying physical media into your server directory manually, you can also mount the ISO images of the installation media into your installation server and use them as a repository. To set up an HTTP, NFS or FTP server that uses ISO images instead of media copies, proceed as follows:

To automatically mount the ISO images at boot time, add the respective mount entries to /etc/fstab. An entry according to the previous example would look like the following:

path_to_iso path_to_repository/productmedium auto loop

There are two ways to set up a DHCP server. For openSUSE, YaST provides a graphical interface to the process. Users can also manually edit the configuration files. For more information about DHCP servers, see also Chapter 12, DHCP.

group { 
  # PXE related stuff 
  # 
  # "next-server" defines the tftp server that will be used 
  next-server ip_tftp_server:
  # 
  # "filename" specifies the pxelinux image on the tftp server 
  # the server runs in chroot under /srv/tftpboot
  filename "pxelinux.0";
  host test {
    hardware ethernet mac_address; 
    fixed-address some_ip_address;
    }
}

Set up a TFTP server with YaST or set it up manually on any other Linux operating system that supports xinetd and TFTP. The TFTP server delivers the boot image to the target system once it boots and sends a request for it.

Some technical background information as well as PXE's complete specifications are available in the Preboot Execution Environment (PXE) Specification (http://www.pix.net/software/pxeboot/archive/pxespec.pdf).

The options listed here are a subset of all the options available for the PXELINUX configuration file.

Prepare the system's BIOS for PXE boot by including the PXE option in the BIOS boot order.

	BIOS Boot Order
Do not place the PXE option ahead of the hard disk boot option in the BIOS. Otherwise this system would try to reinstall itself every time you boot it.

Wake on LAN (WOL) requires the appropriate BIOS option to be enabled prior to the installation. Also, note down the MAC address of the target system. This data is needed to initiate Wake on LAN.

Wake on LAN allows a machine to be turned on by a special network packet containing the machine's MAC address. Because every machine in the world has a unique MAC identifier, you do not need to worry about accidentally turning on the wrong machine.

	Wake on LAN across Different Network Segments
If the controlling machine is not located in the same network segment as the installation target that should be awakened, either configure the WOL requests to be sent as multicasts or remotely control a machine on that network segment to act as the sender of these requests.

The boot options are described in detail in Chapter 1, Installation with YaST. Generally, just 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 Section “Installation Problems” (Appendix A, Help and Troubleshooting, ↑Start-Up).

The menu bar at the bottom screen offers some advanced functionality needed in some setups. Using the F keys, you can specify additional options to pass to the installation routines without having to know the detailed syntax of these parameters (see Section 2.4.2, “Using Custom Boot Options”). A detailed description of the available function keys is available at Section 1.5, “The Boot Screen”.

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

The following table lists all installation scenarios mentioned in this chapter with the required parameters for booting and the corresponding boot options. Just append all of them in the order they appear in this table to get one boot option string that is handed to the installation routines. For example (all in one line):

install=xxx netdevice=xxx hostip=xxx netmask=xxx vnc=xxx vncpassword=xxx
   

Replace all the values xxx in this string with the values appropriate for your setup.

	More Information about linuxrc Boot Options
Find more information about the linuxrc boot options used for booting a Linux system at http://en.opensuse.org/SDB:Linuxrc.

Using any VNC viewer software, you can remotely control the installation of openSUSE from virtually any operating system. This section introduces the setup using a VNC viewer application or a Web browser.

Using SSH, you can remotely control the installation of your Linux machine using any SSH client software.

Every hard disk has a partition table with space for four entries. Every entry in the partition table corresponds to a primary partition or an extended partition. Only one extended partition entry is allowed, however.

A primary partition simply consists of a continuous range of cylinders (physical disk areas) assigned to a particular operating system. With primary partitions you would be limited to four partitions per hard disk, because more do not fit in the partition table. This is why extended partitions are used. Extended partitions are also continuous ranges of disk cylinders, but an extended partition may be divided into logical partitions itself. Logical partitions do not require entries in the partition table. In other words, an extended partition is a container for logical partitions.

If you need more than four partitions, create an extended partition as the fourth partition (or earlier). This extended partition should occupy the entire remaining free cylinder range. Then create multiple logical partitions within the extended partition. The maximum number of logical partitions is 63, independent of the disk type. It does not matter which types of partitions are used for Linux. Primary and logical partitions both function normally.

To create a partition from scratch select Hard Disks and then a hard disk with free space. The actual modification can be done in the Partitions tab:

When you create a new partition or modify an existing partition, you can set various parameters. For new partitions, the default parameters set by YaST are usually sufficient and do not require any modification. To edit your partition setup manually, proceed as follows:

	Resize Filesystems
To resize an existing file system, select the partition and use Resize. Note, that it is not possible to resize partitions while mounted. To resize partitions, unmount the relevant partition before running the partitioner.

After you select a hard disk device (like sda) in the System View pane, you can access the Expert... menu in the lower right part of the Expert Partitioner window. The menu contains the following commands:

After you select the hostname of the computer (the top-level of the tree in the System View pane), you can access the Configure... menu in the lower right part of the Expert Partitioner window. The menu contains the following commands:

The following section includes a few hints and tips on partitioning that should help you make the right decisions when setting up your system.

	Cylinder Numbers
Note, that different partitioning tools may start counting the cylinders of a partition with 0 or with 1. When calculating the number of cylinders, you should always use the difference between the last and the first cylinder number and add one.

From the Expert partitioner, access the LVM configuration by clicking the Volume Management item in the System View pane. However, if a working LVM configuration already exists on your system, it is automatically activated upon entering the initial LVM configuration of a session. In this case, all disks containing a partition (belonging to an activated volume group) cannot be repartitioned. The Linux kernel cannot reread the modified partition table of a hard disk when any partition on this disk is in use. If you already have a working LVM configuration on your system, physical repartitioning should not be necessary. Instead, change the configuration of the logical volumes.

At the beginning of the physical volumes (PVs), information about the volume is written to the partition. To reuse such a partition for other non-LVM purposes, it is advisable to delete the beginning of this volume. For example, in the VG system and PV /dev/sda2, do this with the command dd if=/dev/zero of=/dev/sda2 bs=512 count=1.

	File System for Booting
The file system used for booting (the root file system or /boot) must not be stored on an LVM logical volume. Instead, store it on a normal physical partition.

For more details about LVM, see the Storage Administration Guide.

The LVM enables flexible distribution of hard disk space over several file systems. It was developed because sometimes the need to change the segmenting of hard disk space arises just after the initial partitioning has been done. Because it is difficult to modify partitions on a running system, LVM provides a virtual pool (volume group, VG for short) of memory space from which logical volumes (LVs) can be created as needed. The operating system accesses these LVs instead of the physical partitions. Volume groups can occupy more than one disk, so that several disks or parts of them may constitute one single VG. This way, LVM provides a kind of abstraction from the physical disk space that allows its segmentation to be changed in a much easier and safer way than with physical repartitioning. Background information regarding physical partitioning can be found in Section 3.1.1, “Partition Types” and Section 3.1, “Using the YaST Partitioner”.

Figure 3.2. Physical Partitioning versus LVM¶

Figure 3.2, “Physical Partitioning versus LVM” compares physical partitioning (left) with LVM segmentation (right). On the left side, one single disk has been divided into three physical partitions (PART), each with a mount point (MP) assigned so that the operating system can gain access. On the right side, two disks have been divided into two and three physical partitions each. Two LVM volume groups (VG 1 and VG 2) have been defined. VG 1 contains two partitions from DISK 1 and one from DISK 2. VG 2 contains the remaining two partitions from DISK 2. In LVM, the physical disk partitions that are incorporated in a volume group are called physical volumes (PVs). Within the volume groups, four LVs (LV 1 through LV 4) have been defined. They can be used by the operating system via the associated mount points. The border between different LVs do not need to be aligned with any partition border. See the border between LV 1 and LV 2 in this example.

LVM features:

With these features, LVM is ready for heavily used home PCs or small servers. LVM is well-suited for the user with a growing data stock (as in the case of databases, music archives, or user directories). This would allow file systems that are larger than the physical hard disk. Another advantage of LVM is that up to 256 LVs can be added. However, working with LVM is different from working with conventional partitions. Instructions and further information about configuring LVM is available in the official LVM HOWTO at http://tldp.org/HOWTO/LVM-HOWTO/.

Starting from Kernel version 2.6, LVM version 2 is available, which is backward-compatible with the previous LVM and enables the continued management of old volume groups. When creating new volume groups, decide whether to use the new format or the backward-compatible version. LVM 2 does not require any kernel patches. It makes use of the device mapper integrated in kernel 2.6. This kernel only supports LVM version 2. Therefore, when talking about LVM, this section always refers to LVM version 2.

The YaST LVM configuration can be reached from the YaST Expert Partitioner (see Section 3.1, “Using the YaST Partitioner”) within the Volume Management item in the System View pane. The Expert Partitioner allows you to edit and delete existing partitions and also create new ones that need to be used with LVM. The first task is to create PVs that provide space to a volume group:

3.2.2.1. Creating Volume Groups¶

If no volume group exists on your system, you must add one (see Figure 3.3, “Creating a Volume Group”). It is possible to create additional groups by clicking on Volume Management in the System View pane, and then on Add Volume Group. One single volume group is usually sufficient.

1. Enter a name for the VG, for example, system.

2. Select the desired Physical Extend Size. This value defines the size of a physical block in the volume group. All the disk space in a volume group is handled in blocks of this size.

3. Add the prepared PVs to the VG by selecting the device and clicking on Add. Selecting several devices is possible by holding Ctrl while selecting the devices.

4. Select Finish to make the VG available to further configuration steps.

Figure 3.3. Creating a Volume Group¶

If you have multiple volume groups defined and want to add or remove PVs, select the volume group in the Volume Management list and click Resize. In the following window, you can add or remove PVs to the selected volume group.

3.2.2.2. Configuring Logical Volumes¶

After the volume group has been filled with PVs, define the LVs which the operating system should use in the next dialog. Choose the current volume group and change to the Logical Volumes tab. Add, Edit, Resize, and Delete LVs as needed until all space in the volume group has been occupied. Assign at least one LV to each volume group.

Figure 3.4. Logical Volume Management¶

Click Add and go through the wizard-like pop-up that opens:

1. Enter the name of the LV. For a partition that should be mounted to /home, a self-explanatory name like HOME could be used.

2. Select the size and the number of stripes of the LV. If you have only one PV, selecting more than one stripe is not useful.

3. Choose the filesystem to use on the LV as well as the mount point.

By using stripes it is possible to distribute the data stream in the LV among several PVs (striping). However, striping a volume can only be done over different PVs, each providing at least the amount of space of the volume. The maximum number of stripes equals to the number of PVs, where Stripe "1" means "no striping". Striping only makes sense with PVs on different hard disks, otherwise performance will decrease.

	Striping
YaST cannot, at this point, verify the correctness of your entries concerning striping. Any mistake made here is apparent only later when the LVM is implemented on disk.

If you have already configured LVM on your system, the existing logical volumes can also be used. Before continuing, assign appropriate mount points to these LVs. With Finish, return to the YaST Expert Partitioner and finish your work there.

The YaST RAID configuration can be reached from the YaST Expert Partitioner, described in Section 3.1, “Using the YaST Partitioner”. This partitioning tool enables you to edit and delete existing partitions and create new ones to be used with soft RAID:

For RAID 0 and RAID 1, at least two partitions are needed—for RAID 1, usually exactly two and no more. If RAID 5 is used, at least three partitions are required. It is recommended to utilize partitions of the same size only. The RAID partitions should be located on different hard disks to decrease the risk of losing data if one is defective (RAID 1 and 5) and to optimize the performance of RAID 0. After creating all the partitions to use with RAID, click RAID+Add RAID to start the RAID configuration.

In the next dialog, choose between RAID levels 0, 1, 5, 6 and 10. Then, select all partitions with either the “Linux RAID” or “Linux native” type that should be used by the RAID system. No swap or DOS partitions are shown.

Figure 3.5. RAID Partitions¶

To add a previously unassigned partition to the selected RAID volume, first click the partition then Add. Assign all partitions reserved for RAID. Otherwise, the space on the partition remains unused. After assigning all partitions, click Next to select the available RAID Options.

In this last step, set the file system to use as well as encryption and the mount point for the RAID volume. After completing the configuration with Finish, see the /dev/md0 device and others indicated with RAID in the expert partitioner.

Check the file /proc/mdstat to find out whether a RAID partition has been damaged. In the event of a system failure, shut down your Linux system and replace the defective hard disk with a new one partitioned the same way. Then restart your system and enter the command mdadm /dev/mdX --add /dev/sdX. Replace 'X' with your particular device identifiers. This integrates the hard disk automatically into the RAID system and fully reconstructs it.

Note that although you can access all data during the rebuild, you may encounter some performance issues until the RAID has been fully rebuilt.

Configuration instructions and more details for soft RAID can be found in the HOWTOs at:

Linux RAID mailing lists are available, such as http://marc.info/?l=linux-raid.

The graphical splash screen with the boot menu is based on the GRUB configuration file /boot/grub/menu.lst, which contains all information about all partitions or operating systems that can be booted by the menu.

Every time the system is booted, GRUB loads the menu file from the file system. For this reason, GRUB does not need to be reinstalled after every change to the file. Use the YaST boot loader to modify the GRUB configuration as described in Section 6.2, “Configuring the Boot Loader with YaST”.

The menu file contains commands. The syntax is very simple. Every line contains a command followed by optional parameters separated by spaces like in the shell. For historical reasons, some commands permit an = in front of the first parameter. Comments are introduced by a hash (#).

To identify the menu items in the menu overview, set a title for every entry. The text (including any spaces) following the keyword title is displayed as a selectable option in the menu. All commands up to the next title are executed when this menu item is selected.

The simplest case is the redirection to boot loaders of other operating systems. The command is chainloader and the argument is usually the boot block of another partition, in GRUB block notation. For example:

chainloader (hd0,3)+1

The device names in GRUB are explained in Section 6.1.1.1, “Naming Conventions for Hard Disks and Partitions”. This example specifies the first block of the fourth partition of the first hard disk.

Use the command kernel to specify a kernel image. The first argument is the path to the kernel image in a partition. The other arguments are passed to the kernel on its command line.

If the kernel does not have built-in drivers for access to the root partition or a recent Linux system with advanced hotplug features is used, initrd must be specified with a separate GRUB command whose only argument is the path to the initrd file. Because the loading address of the initrd is written into the loaded kernel image, the command initrd must follow after the kernel command.

The command root simplifies the specification of kernel and initrd files. The only argument of root is a device or a partition. This device is used for all kernel, initrd, or other file paths for which no device is explicitly specified until the next root command.

The boot command is implied at the end of every menu entry, so it does not need to be written into the menu file. However, if you use GRUB interactively for booting, you must enter the boot command at the end. The command itself has no arguments. It merely boots the loaded kernel image or the specified chain loader.

After writing all menu entries, define one of them as the default entry. Otherwise, the first one (entry 0) is used. You can also specify a time-out in seconds after which the default entry should boot. timeout and default usually precede the menu entries. An example file is described in Section 6.1.1.2, “An Example Menu File”.

(hd0,0)   first primary partition of the first hard disk
(hd0,1)   second primary partition
(hd0,2)   third primary partition
(hd0,3)   fourth primary partition (usually an extended partition)
(hd0,4)   first logical partition
(hd0,5)   second logical partition

(hd0,0)/boot/vmlinuz

gfxmenu (hd0,4)/boot/message
color white/blue black/light-gray
default 0
timeout 8

title linux
   root (hd0,4)
   kernel /boot/vmlinuz root=/dev/sda7 vga=791 resume=/dev/sda9
   initrd /boot/initrd

title windows
   rootnoverify (hd0,0)
   chainloader +1

title floppy
   rootnoverify (hd0,0)
   chainloader (fd0)+1

title failsafe
   root (hd0,4)
   kernel /boot/vmlinuz.shipped root=/dev/sda7 ide=nodma \
   apm=off acpi=off vga=normal nosmp maxcpus=0 3 noresume
   initrd /boot/initrd.shipped

6.1.1.3. Editing Menu Entries during the Boot Procedure¶

In the graphical boot menu, select the operating system to boot with the arrow keys. If you select a Linux system, you can enter additional boot parameters at the boot prompt. To edit individual menu entries directly, press Esc to exit the splash screen and get to the GRUB text-based menu then press E. Changes made in this way only apply to the current boot and are not adopted permanently.

	Keyboard Layout during the Boot Procedure
The US keyboard layout is the only one available when booting. See Figure “US Keyboard Layout” (↑Start-Up).

Editing menu entries facilitates the repair of a defective system that can no longer be booted, because the faulty configuration file of the boot loader can be circumvented by manually entering parameters. Manually entering parameters during the boot procedure is also useful for testing new settings without impairing the native system.

After activating the editing mode, use the arrow keys to select the menu entry of the configuration to edit. To make the configuration editable, press E again. In this way, edit incorrect partitions or path specifications before they have a negative effect on the boot process. Press Enter to exit the editing mode and return to the menu. Then press B to boot this entry. Further possible actions are displayed in the help text at the bottom.

To enter changed boot options permanently and pass them to the kernel, open the file menu.lst as the user root and append the respective kernel parameters to the existing line, separated by spaces:

title linux
   root(hd0,0)
     kernel /vmlinuz root=/dev/sda3 additional parameter
   initrd /initrd

GRUB automatically adopts the new parameters the next time the system is booted. Alternatively, this change can also be made with the YaST boot loader module. Append the new parameters to the existing line, separated by spaces.

The file device.map maps GRUB and BIOS device names to Linux device names. In a mixed system containing PATA (IDE) and SCSI hard disks, GRUB must try to determine the boot sequence by a special procedure, because GRUB may not have access to the BIOS information on the boot sequence. GRUB saves the result of this analysis in the file /boot/grub/device.map. Example device.map files for a system on which the boot sequence in the BIOS is set to PATA before SCSI could look as follows:

(fd0)  /dev/fd0
(hd0)  /dev/sda
(hd1)  /dev/sdb

or

(fd0)  /dev/fd0
(hd0)  /dev/disk-by-id/DISK1 ID
(hd1)  /dev/disk-by-id/DISK2 ID

Because the order of PATA (IDE), SCSI and other hard disks depends on various factors and Linux is not able to identify the mapping, the sequence in the file device.map can be set manually. If you encounter problems when booting, check if the sequence in this file corresponds to the sequence in the BIOS and use the GRUB prompt to modify it temporarily, if necessary. After the Linux system has booted, the file device.map can be edited permanently with the YaST boot loader module or an editor of your choice.

After manually changing device.map, execute the following command to reinstall GRUB. This command causes the file device.map to be reloaded and the commands listed in grub.conf to be executed:

grub --batch < /etc/grub.conf

The third important GRUB configuration file after menu.lst and device.map is /etc/grub.conf. This file contains the commands, parameters and options the GRUB shell needs for installing the boot loader correctly:

setup --stage2=/boot/grub/stage2 --force-lba (hd0,1) (hd0,1)
   quit

This command tells GRUB to automatically install the boot loader to the second partition on the first hard disk (hd0,1) using the boot images located on the same partition. The --stage2=/boot/grub/stage2 parameter is needed to install the stage2 image from a mounted file system. Some BIOSes have a faulty LBA support implementation, --force-lba provides a solution to ignore them.

This configuration file is only used when configuring the bootloader with YaST and every time a new kernel is installed. It is evaluated by the perl-bootloader library which modifies the bootloader configuration file (for example /boot/grub/menu.lst for GRUB) accordingly. /etc/sysconfig/bootloader is not a GRUB specific configuration file - the values are applied to any bootloader installed on openSUSE.

	Bootloader Configuration after a Kernel Update
Every time a new kernel is installed, the perl bootloader writes a new bootloader configuration file (for example /boot/grub/menu.lst for GRUB) using the defaults specified in /etc/sysconfig/bootloader. If you are using a customized set of kernel parameters, make sure to adjust the relevant defaults in /etc/sysconfig/bootloader according to your needs.

Even before the operating system is booted, GRUB enables access to file systems. Users without root permissions can access files in your Linux system to which they have no access once the system is booted. To block this kind of access or to prevent users from booting certain operating systems, set a boot password.

	Boot Password and Splash Screen
If you use a boot password for GRUB, the usual splash screen is not displayed.

As the user root, proceed as follows to set a boot password:

To change the system that is booted by default, proceed as follows:

To modify the location of the boot loader, follow these steps:

The boot loader does not boot the default system immediately. During the time-out, you can select the system to boot or write some kernel parameters. To set the boot loader time-out, proceed as follows:

	Timeout of 0 Seconds
When setting the timeout to 0 seconds, you will not be able to access GRUB during boot time. When having set the default boot option to a non-Linux operation system at the same time, this effectively disables access to the Linux system.

Using this YaST module, you can also set a password to protect booting. This gives you an additional level of security.

If your computer has more than one hard disk, you can specify the boot sequence of the disks to match the BIOS setup of the machine (see Section 6.1.2, “The File device.map”). To do so, proceed as follows:

Advanced boot options can be configured via Boot Loader Installation+Boot Loader Options. Normally, it should not be necessary to change the default settings.

Set the boot loader type in Boot Loader Installation. The default boot loader in openSUSE is GRUB. To use LILO or ELILO, proceed as follows:

	LILO is unsupported
Using LILO is not recommended—it is unsupported on openSUSE. Only use it in special cases.

During the conversion, the old GRUB configuration is saved to the disk. To use it, simply change the boot loader type back to GRUB and choose Restore Configuration Saved before Conversion. This action is available only on an installed system.

	Custom Boot Loader
To use a boot loader other than GRUB or LILO, select Do Not Install Any Boot Loader. Read the documentation of your boot loader carefully before choosing this option.

Bash is the default system shell. When used as a login shell, it reads several initialization files. Bash processes them in the order they appear in this list:

Make custom settings in ~/.profile or ~/.bashrc. To ensure the correct processing of these files, it is necessary to copy the basic settings from /etc/skel/.profile or /etc/skel/.bashrc into the home directory of the user. It is recommended to copy the settings from /etc/skel after an update. Execute the following shell commands to prevent the loss of personal adjustments:

mv ~/.bashrc ~/.bashrc.old
cp /etc/skel/.bashrc ~/.bashrc
mv ~/.profile ~/.profile.old
cp /etc/skel/.profile ~/.profile

Then copy personal adjustments back from the *.old files.

If you want to run commands regularly and automatically in the background at predefined times, cron is the tool to use. cron is driven by specially formatted time tables. Some of them come with the system and users can write their own tables if needed.

The cron tables are located in /var/spool/cron/tabs. /etc/crontab serves as a systemwide cron table. Enter the username to run the command directly after the time table and before the command. In Example 7.1, “Entry in /etc/crontab”, root is entered. Package-specific tables, located in /etc/cron.d, have the same format. See the cron man page (man cron).

1-59/5 * * * *   root   test -x /usr/sbin/atrun && /usr/sbin/atrun

You cannot edit /etc/crontab by calling the command crontab -e. This file must be loaded directly into an editor, then modified and saved.

A number of packages install shell scripts to the directories /etc/cron.hourly, /etc/cron.daily, /etc/cron.weekly and /etc/cron.monthly, whose execution is controlled by /usr/lib/cron/run-crons. /usr/lib/cron/run-crons is run every 15 minutes from the main table (/etc/crontab). This guarantees that processes that may have been neglected can be run at the proper time.

To run the hourly, daily or other periodic maintenance scripts at custom times, remove the time stamp files regularly using /etc/crontab entries (see Example 7.2, “/etc/crontab: Remove Time Stamp Files”, which removes the hourly one before every full hour, the daily one once a day at 2:14 a.m., etc.).

59 *  * * *     root  rm -f /var/spool/cron/lastrun/cron.hourly
14 2  * * *     root  rm -f /var/spool/cron/lastrun/cron.daily
29 2  * * 6     root  rm -f /var/spool/cron/lastrun/cron.weekly
44 2  1 * *     root  rm -f /var/spool/cron/lastrun/cron.monthly

Or you can set DAILY_TIME in /etc/sysconfig/cron to the time at which cron.daily should start. The setting of MAX_NOT_RUN ensures that the daily tasks get triggered to run, even if the user did not turn on the computer at the specified DAILY_TIME for a longer period of time. The maximum value of MAX_NOT_RUN is 14 days.

The daily system maintenance jobs are distributed to various scripts for reasons of clarity. They are contained in the package aaa_base. /etc/cron.daily contains, for example, the components suse.de-backup-rpmdb, suse.de-clean-tmp or suse.de-cron-local.

There are a number of system services (daemons) that, along with the kernel itself, regularly record the system status and specific events onto log files. This way, the administrator can regularly check the status of the system at a certain point in time, recognize errors or faulty functions and troubleshoot them with pinpoint precision. These log files are normally stored in /var/log as specified by FHS and grow on a daily basis. The logrotate package helps control the growth of these files.

Configure logrotate with the file /etc/logrotate.conf. In particular, the include specification primarily configures the additional files to read. Programs that produce log files install individual configuration files in /etc/logrotate.d. For example, such files ship with the packages apache2 (/etc/logrotate.d/apache2) and syslogd (/etc/logrotate.d/syslog).

# see "man logrotate" for details
# rotate log files weekly
weekly

# keep 4 weeks worth of backlogs
rotate 4

# create new (empty) log files after rotating old ones
create

# uncomment this if you want your log files compressed
#compress

# RPM packages drop log rotation information into this directory
include /etc/logrotate.d

# no packages own lastlog or wtmp - we'll rotate them here
#/var/log/wtmp {
#    monthly
#    create 0664 root utmp
#    rotate 1
#}

# system-specific logs may be also be configured here.

logrotate is controlled through cron and is called daily by /etc/cron.daily/logrotate.

The create option reads all settings made by the administrator in /etc/permissions*. Ensure that no conflicts arise from any personal modifications.

locate, a command for quickly finding files, is not included in the standard scope of installed software. If desired, install the package findutils-locate. The updatedb process is started automatically every night or about 15 minutes after booting the system.

With the ulimit (user limits) command, it is possible to set limits for the use of system resources and to have these displayed. ulimit is especially useful for limiting available memory for applications. With this, an application can be prevented from co-opting too much of the system resources and slowing or even hanging up the operating system.

ulimit can be used with various options. To limit memory usage, use the options listed in Table 7.1, “ulimit: Setting Resources for the User”.

Systemwide entries can be made in /etc/profile. There, enable creation of core files (needed by programmers for debugging). A normal user cannot increase the values specified in /etc/profile by the system administrator, but can make special entries in ~/.bashrc.

# Limits maximum resident set size (physical memory):
ulimit -m 98304
 
# Limits of virtual memory:
ulimit -v 98304

Memory allocations must be specified in KB. For more detailed information, see man bash.

Not all shells support ulimit directives. PAM (for instance, pam_limits) offers comprehensive adjustment possibilities if you depend on encompassing settings for these restrictions.

The free command displays the total amount of free and used physical memory and swap space in the system, as well as the buffers and cache consumed by the kernel. The concept of available RAM dates back to before the days of unified memory management. The slogan free memory is bad memory applies well to Linux. As a result, Linux has always made the effort to balance out caches without actually allowing free or unused memory.

Basically, the kernel does not have direct knowledge of any applications or user data. Instead, it manages applications and user data in a page cache. If memory runs short, parts of it are written to the swap partition or to files, from which they can initially be read with the help of the mmap command (see man mmap).

The kernel also contains other caches, such as the slab cache, where the caches used for network access are stored. This may explain the differences between the counters in /proc/meminfo. Most, but not all, of them can be accessed via /proc/slabinfo.

However, if your goal is to find out how much RAM is currently being used, find this information in /proc/meminfo.

For some GNU applications (such as tar), the man pages are no longer maintained. For these commands, use the --help option to get a quick overview of the info pages, which provide more in-depth instructions. Info is GNU's hypertext system. Read an introduction to this system by entering info info. Info pages can be viewed with Emacs by entering emacs -f info or directly in a console with info. You can also use tkinfo, xinfo or the help system to view info pages.

To read a man page enter man man_page. If a man page with the same name exists in different sections, they will all be listed with the corresponding section numbers. Select the one to display. If you don't enter a section number within a few seconds, the first man page will be displayed.

If you want to change this to the default system behavior, set MAN_POSIXLY_CORRECT=1 in a shell initialization file such as ~/.bashrc.

GNU Emacs is a complex work environment. The following sections cover the configuration files processed when GNU Emacs is started. More information is available at http://www.gnu.org/software/emacs/.

On start-up, Emacs reads several files containing the settings of the user, system administrator and distributor for customization or preconfiguration. The initialization file ~/.emacs is installed to the home directories of the individual users from /etc/skel. .emacs, in turn, reads the file /etc/skel/.gnu-emacs. To customize the program, copy .gnu-emacs to the home directory (with cp /etc/skel/.gnu-emacs ~/.gnu-emacs) and make the desired settings there.

.gnu-emacs defines the file ~/.gnu-emacs-custom as custom-file. If users make settings with the customize options in Emacs, the settings are saved to ~/.gnu-emacs-custom.

With openSUSE, the emacs package installs the file site-start.el in the directory /usr/share/emacs/site-lisp. The file site-start.el is loaded before the initialization file ~/.emacs. Among other things, site-start.el ensures that special configuration files distributed with Emacs add-on packages, such as psgml, are loaded automatically. Configuration files of this type are located in /usr/share/emacs/site-lisp, too, and always begin with suse-start-. The local system administrator can specify systemwide settings in default.el.

More information about these files is available in the Emacs info file under Init File: info:/emacs/InitFile. Information about how to disable the loading of these files (if necessary) is also provided at this location.

The components of Emacs are divided into several packages:

You should always set the language and country codes together. Language settings follow the standard ISO 639 available at http://www.evertype.com/standards/iso639/iso639-en.html and http://www.loc.gov/standards/iso639-2/. Country codes are listed in ISO 3166 available at http://www.din.de/gremien/nas/nabd/iso3166ma/codlstp1/en_listp1.html.

It only makes sense to set values for which usable description files can be found in /usr/lib/locale. Additional description files can be created from the files in /usr/share/i18n using the command localedef. The description files are part of the glibc-i18ndata package. A description file for en_US.UTF-8 (for English and United States) can be created with:

localedef -i en_US -f UTF-8 en_US.UTF-8

In former releases, it was necessary to run SuSEconfig after doing any changes to /etc/sysconfig/language. SuSEconfig then wrote the changes to /etc/SuSEconfig/profile and /etc/SuSEconfig/csh.login. Upon login, these files were read by /etc/profile (for the Bash) or by /etc/csh.login (for the tcsh) .

In recent releases, /etc/SuSEconfig/profile has been replaced with /etc/profile.d/lang.sh, and /etc/SuSEconfig/csh.login with /etc/profile.de/lang.csh. But if they exist, both legacy file are still read upon login.

The process chain is now as follows:

This ensures that any changes to /etc/sysconfig/language are available at the next login to the respective shell, without having to run SuSEconfig first.

Users can override the system defaults by editing their ~/.bashrc accordingly. For instance, if you do not want to use the systemwide en_US for program messages, include LC_MESSAGES=es_ES so that messages are displayed in Spanish instead.

If you are not satisfied with locale system defaults, change the settings in ~/.i18n according to the Bash scripting syntax. Entries in ~/.i18n override system defaults from /etc/sysconfig/language. Use the same variable names but without the RC_ namespace prefixes. For example, use LANG instead of RC_LANG:

LANG=cs_CZ.UTF-8
LC_COLLATE=C

Files in the category Messages are, as a rule, only stored in the corresponding language directory (like en) to have a fallback. If you set LANG to en_US and the message file in /usr/share/locale/en_US/LC_MESSAGES does not exist, it falls back to /usr/share/locale/en/LC_MESSAGES.

A fallback chain can also be defined, for example, for Breton to French or for Galician to Spanish to Portuguese:

LANGUAGE="br_FR:fr_FR"

LANGUAGE="gl_ES:es_ES:pt_PT"

If desired, use the Norwegian variants Nynorsk and Bokmål instead (with additional fallback to no):

LANG="nn_NO"

LANGUAGE="nn_NO:nb_NO:no"

or

LANG="nb_NO"

LANGUAGE="nb_NO:nn_NO:no"

Note that in Norwegian, LC_TIME is also treated differently.

One problem that can arise is a separator used to delimit groups of digits not being recognized properly. This occurs if LANG is set to only a two-letter language code like de, but the definition file glibc uses is located in /usr/share/lib/de_DE/LC_NUMERIC. Thus LC_NUMERIC must be set to de_DE to make the separator definition visible to the system.

Creating keys you can choose from several different operators, depending on the type of key you want to create. Match keys will normally just be used to find a value that either matches or explicitly mismatches the search value. Match keys contain either of the following operators:

Any of the following operators can be used with assign keys:

udev rules support the use of placeholders and substitutions. Use them in a similar fashion as you would do in any other scripts. The following substitutions can be used with udev rules:

Match keys describe conditions that must be met before a udev rule can be applied. The following match keys are available:

In contrast to the match keys described above, assign keys do not describe conditions that must be met. They assign values, names and actions to the device nodes maintained by udev.