Linux System Administration 2

Question 1

Which command displays the current runlevel on a systemd-based Linux system?

Accepted Answer

who -r

Answer

The `who -r` command displays the current runlevel on both SysV and systemd systems.

Question 2

What does the `/etc/fstab` file control?

Accepted Answer

Filesystem mount points and options at boot

Answer

The `/etc/fstab` file defines how disk partitions and filesystems are mounted automatically at boot.

Question 3

Which `systemctl` subcommand prevents a service from starting automatically at boot without stopping it if currently running?

Accepted Answer

systemctl disable

Answer

`systemctl disable` removes the service from startup targets without affecting its current running state.

Question 4

A system has 4GB RAM and no swap. What is the recommended swap size according to Red Hat guidelines for hibernation support?

Accepted Answer

8GB

Answer

Red Hat recommends swap equal to RAM + square root of RAM for hibernation; for 4GB RAM that rounds up to 8GB.

Question 5

What is the purpose of the `nice` command in Linux?

Accepted Answer

Adjust process scheduling priority

Answer

`nice` launches a command with a modified scheduling priority (niceness value from -20 to 19).

Linux Practice Test