Linux System Administration 3

Question 1

Which command would you use to add a user to a supplementary group without changing their primary group?

Accepted Answer

usermod -aG groupname username

Answer

`usermod -aG` appends the user to the specified group while preserving existing group memberships.

Question 2

What is the effect of setting the SUID bit on an executable file?

Accepted Answer

The file runs with the permissions of the file owner

Answer

SUID (Set User ID) causes the executable to run with the privileges of the file's owner, not the user who runs it.

Question 3

You need to schedule a one-time task to run at 3:30 PM today. Which command is correct?

Accepted Answer

at 3:30pm

Answer

The `at` command schedules a one-time task at a specified time, unlike `cron` which handles recurring tasks.

Question 4

Which `/proc` entry shows the currently loaded kernel modules?

Accepted Answer

/proc/modules

Answer

`/proc/modules` lists all currently loaded kernel modules, equivalent to the output of `lsmod`.

Question 5

What does `journalctl --since '1 hour ago'` do?

Accepted Answer

Shows all journal entries from the last hour until now

Answer

`--since` filters journal output to show entries from the specified time to the present.

Linux Practice Test