Linux System Administration 5

Question 1

Which command updates the initramfs image on an Ubuntu/Debian system?

Accepted Answer

update-initramfs -u

Answer

`update-initramfs -u` rebuilds the initramfs for the current kernel on Debian-based systems.

Question 2

What is the purpose of the `chroot` command?

Accepted Answer

Change the apparent root directory for a process

Answer

`chroot` runs a command with a specified directory as the apparent filesystem root, isolating it from the real root.

Question 3

Which file controls the maximum number of open file descriptors system-wide on a Linux system?

Accepted Answer

/proc/sys/fs/file-max

Answer

`/proc/sys/fs/file-max` holds the system-wide maximum number of open file descriptors the kernel allows.

Question 4

You need to zero out a disk before decommissioning it securely. Which command is appropriate?

Accepted Answer

shred -vz /dev/sdX

Answer

`shred -vz` overwrites the device multiple times and then zeros it, making data recovery very difficult.

Question 5

What does `ss -s` display?

Accepted Answer

A summary of socket statistics by protocol

Answer

`ss -s` prints a summary showing the total number of sockets broken down by type and state.

Linux Practice Test