RHCSA Linux Essentials Flashcards

Which command searches for the string 'error' case-insensitively in all .log files under /var/log?

Answer: grep -ri 'error' /var/log/

`grep -r` recurses through directories and `-i` makes the search case-insensitive, covering all .log files.

What does the `tar -xzf archive.tar.gz -C /opt/` command do?

Answer: Extracts archive.tar.gz into the /opt/ directory

The flags -x (extract), -z (gzip), -f (file) combined with -C specify the extraction destination directory.

Which command sets a user account to expire on December 31, 2026?

Answer: Both B and C are correct

Both `usermod -e` and `chage -E` accept a YYYY-MM-DD date and set the account expiration date.

A volume group `vg_data` has 10 GiB free. Which command creates a 4 GiB logical volume named `lv_logs`?

Answer: lvcreate -L 4G -n lv_logs vg_data

`lvcreate -L 4G -n lv_logs vg_data` creates a new 4 GiB logical volume named lv_logs in the specified volume group.

Which configuration file defines the DNS search domain and nameservers for a RHEL system?

Answer: /etc/resolv.conf

/etc/resolv.conf contains the `nameserver` and `search` directives used by the resolver library.

What is the correct way to redirect both stdout and stderr to a file named output.txt?

Answer: command &> output.txt

`&>` is bash shorthand that redirects both file descriptor 1 (stdout) and 2 (stderr) to the same file.

Which command would display the last 50 lines of the journal for the sshd service?

Answer: journalctl -u sshd -n 50

`journalctl -u sshd -n 50` filters journal entries for the sshd unit and limits output to the last 50 lines.