https://documentation.suse.com/sles/12-SP4/html/SLES-all/cha-grub2.html

To add two new custom items to the GRUB2 boot menu, you should modify the /boot/grub2/custom.cfg file. This file can contain custom menu entries that will be added to the end of the GRUB2 menu. The syntax and format of this file are similar to /boot/grub2/grub.cfg file. You do not need to run grub2-mkconfig after modifying this file. References:https://documentation.suse.com/sles/15-SP3/html/SLES-all/sec-grub2-custom.html

The file that contains the list of DNS servers SLES will contact is /etc/resolv.conf. This file specifies one or more nameserver addresses that will be used to resolve hostnames to IP addresses. It may also contain other options such as search domains, sort lists, etc. The /etc/resolv.conf file can be generated automatically by network configuration tools or edited manually by the administrator. References:https://documentation.suse.com/sles/15-SP3/html/SLES-all/sec-network-dns.html#sec-network-dns-resolv.conf

The command that allows you to create an alias command is alias. The alias command can be used to define a short name or abbreviation for another command or sequence of commands. The syntax of the alias command is alias name=‘command’. For example, alias c=‘clear’ will create an alias named c for the clear command. You can then type c to run the clear command. To remove an alias, you can use unalias name. References:https://documentation.suse.com/sles/15-SP3/html/SLES-all/cha-bash.html#sec-bash-alias

https://documentation.suse.com/sles/12-SP4/html/SLES-all/cha-security-acls.html

The three permissions available on posix file systems are read, write, and execute. The read permission allows the user to view the contents of a file or directory. The write permission allows the user to modify or delete a file or directory. The execute permission allows the user to run a file as a program or change into a directory. References:https://documentation.suse.com/sles/15-SP3/html/SLES-all/sec-file-permissions.html#sec-file-permissions-types

By default, the VNC Client and the VNC server daemon use a self-signed SSL certificate for secure communications. The VNC server generates a self-signed certificate when it is started for the first time. The VNC Client will prompt the user to accept or reject the certificate when connecting to the server. Alternatively, the user can provide a custom certificate for the VNC server or disable encryption if desired. References:https://documentation.suse.com/sles/15-SP3/html/SLES-all/sec-vnc-security.html

The name of the system logging facility in SUSE Linux Enterprise is syslog-ng. It is a flexible and scalable implementation of the syslog protocol that can handle various types of log messages from different sources and destinations. References:https://documentation.suse.com/sles/15-SP3/html/SLES-all/cha-syslog.html

The execute permission on a directory means you can use the cd command to change into the directory. It also means you can access the files and subdirectories inside the directory, if you have read permission on them. The execute permission does not affect the visibility or exportability of the directory. References:https://documentation.suse.com/sles/15-SP3/html/SLES-all/sec-file-permissions.html

If you are setting up a SLES 15 server that will require very large data volumes and journaling capabilities, the best choice for your data volumes is XFS. XFS is a high-performance and scalable file system that supports large files and file systems, online defragmentation and resizing, metadata checksums, and other features. XFS also provides journaling capabilities that ensure data consistency and integrity in case of system crashes or power failures. XFS is the default file system for data partitions in SLES 15. References:https://documentation.suse.com/sles/15-SP3/html/SLES-all/cha-filesystems.html#sec-filesystems-xfs

Assuming the default value for umask, which is 022, the permissions on new files would be set to 644 and the permissions on new directories would be set to 755. The umask value is subtracted from the base permissions of 666 for files and 777 for directories to determine the actual permissions. For example, 666 - 022 = 644 for files and 777 - 022 = 755 for directories. References:https://documentation.suse.com/sles/15-SP3/html/SLES-all/sec-file-permissions.html#sec-file-permissions-umask

The statement that is true regarding the life cycle support for SUSE Linux platform products is that the support for SLE platforms has a 13 year life cycle: 10 years of general support and 3 years of extended support. General support includes security updates, bug fixes, feature enhancements, and technical support. Extended support includes security updates and technical support only. Service packs have a different life cycle depending on their release date and version. References:https://www.suse.com/lifecycle/

The ip route show or ip r s commands will display the routing table on a Linux system. The routing table contains information about how to reach different network destinations. The cat /etc/sysconfig/routes command will display the static routes configuration file, which may not reflect the current routing table. The other commands are either invalid or unrelated to routing. References:https://documentation.suse.com/sles/15-SP3/html/SLES-all/sec-network-routing.html

To make the third menu entry of your GRUB2 boot menu your default menu selection, you need to do the following tasks:

• Edit the /etc/default/grub file and set GRUB_DEFAULT to 2
• Run the grub2-mkconfig command

The /etc/default/grub file contains various settings for the GRUB2 boot loader, such as the default menu entry, the timeout value, the theme file, etc. The GRUB_DEFAULT setting can be set to a numeric value that corresponds to the menu entry index (starting from 0), or a string value that matches the menu entry title. The grub2-mkconfig command will generate a new /boot/grub2/grub.cfg file based on the settings in /etc/default/grub and other configuration files and scripts. References: https://documentation.suse.com/sles/15-SP3/html/SLES-all/sec-grub2-config.html#sec-grub2-config-default

To add additional physical volumes to an existing volume group, use the vgextend command. The vgextend command increases a volume group's capacity by adding one or more free physical volumes.

https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/4/html/cluster_logical_volume_manager/vg_grow#:~:text=To%20add%20additional%20physical%20volumes,or%20more%20free%20phys ical%20volumes.

The command that is used to add new physical volumes to an existing volume group is vgextend. This command will extend a volume group by adding one or more physical volumes to it. The physical volumes must be initialized with pvcreate before they can be added to a volume group. References:https://documentation.suse.com/sles/15-SP3/html/SLES-all/sec-lvm-vgs.html#sec-lvm-vgs-add-pv

The screen command will allow you to create and manage multiple terminal sessions that can be detached and resumed later. You can use the screen command to start a new session, then detach it with Ctrl-a d, and reattach it from another location with screen -r. References:https://documentation.suse.com/sles/15-SP3/html/SLES-all/cha-screen.html

The initrd file is an initial ramdisk image that contains the necessary drivers and tools to mount the root file system and start the boot process. It is usually located in the /boot directory along with the kernel image (vmlinuz). References:https://documentation.suse.com/sles/15-SP3/html/SLES-all/sec-boot-initrd.html

The two commands that are commonly used to compile and install from source code are ./configure and make install. The ./configure command will check the system for dependencies, set variables, and generate a Makefile. The make install command will use the Makefile to compile the source code and copy the binaries and files to the appropriate locations. References:https://documentation.suse.com/sles/15-SP3/html/SLES-all/sec-software-install-source.html

Save a File in Vim / Vi #The command to save a file in Vim is :w.

To save the file without exiting the editor, switch back to normal mode by pressing Esc, type :w and hit Enter.

https://linuxize.com/post/how-to-save-file-in-vim-quit-editor/

The w command will save the current file without exiting Vim. It stands for write. The other commands are either invalid or will exit Vim after saving. References:https://documentation.suse.com/sles/15-SP3/html/SLES-all/cha-vim.html#sec-vim-save

The command and options to remove repository number 4 are zypper rr 4. This command will remove the repository with the alias or number 4 from the system. It will also delete anyassociated cache data and metadata. To list the repositories on the system, you can use zypper lr or zypper repos. References:https://documentation.suse.com/sles/15-SP3/html/SLES-all/sec-zypper.html#sec-zypper-repos