The command that will set the sticky bit on a directory called devops with 755 file permission is chmod 1755 devops. This command will use chmod to change the mode of the directory devops to 1755, which means that the owner has read, write, and execute permissions (7), the group has read and execute permissions (5), and others have read and execute permissions (5). The first digit 1 indicates that the sticky bit is set on the directory, which is a special permission that prevents users from deleting or renaming files in the directory that they do not own.
The other options are not correct commands for setting the sticky bit on a directory. The chown -s 755 devops command is invalid because chown is used to change the owner and group of files or directories, not their permissions. The -s option for chown is used to remove a symbolic link, not to set the sticky bit. The chown
1755 devops command is also invalid because chown does not accept numeric arguments for changing permissions. The chmod -s 755 devops command will remove the sticky bit from the directory devops, not set it. References: chmod(1) - Linux manual page; How to Use SUID, SGID, and Sticky Bits on Linux

The issue is that the administrator did not set the default target to graphical.target. A target is a unit of systemd that groups together other units by a common purpose or state. The graphical.target is a target that starts the graphical user interface (GUI) along with other services. The administrator used the command systemct1 isolate graphical.target to switch to this target temporarily, but this does not change the default target that is activated at boot time. To make this change permanent, the administrator should have used the command systemct1 set-default graphical.target, which creates a symbolic link from /etc/systemd/system
/default.target to /usr/lib/systemd/system/graphical.target.
The other options are not correct explanations for the issue. The administrator did reboot the server properly by using systemct1 reboot, which shuts down and restarts the system cleanly. The administrator did not need to set the default target to basic.target, which is a minimal target that only starts essential services. The administrator did not shut down the server improperly, which could have caused file system corruption or data loss, but not affect the default target. References: systemct1(1) - Linux manual page; How to Change Runlevels (targets) in SystemD

The command that would address the memory-related issue is kill -9 8321. This command will send a SIGKILL signal to the process with the PID 8321, which is the mysqld process that is using 99.7% of the available memory according to the top output. The SIGKILL signal will terminate the process immediately and free up the memory it was using. However, this command should be used with caution as it may cause data loss or corruption if the process was performing some critical operations.
The other options are not correct commands for addressing the memory-related issue. The top -p 8321 command will only display information about the process with the PID 8321, but will not kill it or reduce its memory usage. The renice -10 8321 command will change the priority (niceness) of the process with the PID
8321 to -10, which means it will have a higher scheduling priority, but this will not affect its memory consumption. The free 8321 command is invalid because free does not take a PID as an argument; free only displays information about the total, used, and free memory in the system. References: How to troubleshoot Linux server memory issues; kill(1) - Linux manual page

The RPM database can sometimes become corrupted, which prevents package installations and other RPM operations from functioning correctly. The --rebuilddb option for rpmdb is used to rebuild the database. This command regenerates the database, fixing any corruption issues and ensuring that the package metadata is restored to a usable state.

The gzip command with the -c flag outputs the compressed data to standard output, which can then be redirected to create a .gz file. This approach maintains the original file while creating a compressed version.