XK0-006 Practice Test 3 — 10 Questions

Question 1

A systems administrator needs to ensure that a custom service runs with a specific priority on a Linux server. Which command should the administrator use to achieve this?

Accepted Answer

nice -n -10 /usr/local/bin/myservice. The `nice` command adjusts the CPU scheduling priority of a process at launch time. Using `nice -n -10` sets a higher priority (lower nice value) for the new service, ensuring it runs with the specified priority from the start. This directly meets the requirement to run a custom service with a specific priority.

Answer

renice -10 -p 1234

Answer

ionice -c 2 -n 0 -p 1234

Answer

chrt -r 99 /usr/local/bin/myservice

Question 2

A Linux engineer is investigating high disk I/O on a server. Which command provides disk I/O statistics including %util, await, r/s, and w/s?

Accepted Answer

iostat -x 1. iostat reports CPU and disk I/O statistics, with columns like %util, await, r/s, and w/s.

Answer

sar -b

Answer

vmstat 1 5

Answer

free -h

Question 3

A security engineer needs to verify the authenticity of a downloaded file using its detached GPG signature (file.sig). Which command should be used?

Accepted Answer

gpg --verify file.sig. The `gpg --verify file.sig` command is used to verify the authenticity of a file using its detached GPG signature. The detached signature file (file.sig) contains the cryptographic signature, and GPG checks it against the original file (which must be present in the same directory with the same base name) using the signer's public key from the local keyring. This confirms that the file was signed by the holder of the corresponding private key and has not been tampered with.

Answer

gpg --sign file

Answer

gpg --list-keys

Answer

gpg --decrypt file.gpg

Question 4

Which TWO tools are specifically designed to detect rootkits on a Linux system?

Accepted Answer

rkhunter. rkhunter (B) is a dedicated rootkit hunter that scans for known rootkit signatures, suspicious files, and hidden processes on Linux, making it specifically designed for rootkit detection. chkrootkit (E) is likewise a purpose-built tool that checks system binaries and common rootkit infection vectors on Linux. By contrast, lsof (A) only lists open files and associated processes, netstat (C) merely displays network connections and routing tables, and clamav (D) is an antivirus scanner targeting malware such as viruses and trojans rather than rootkits specifically, so none of these are specifically designed for rootkit detection.

Answer

lsof

Answer

netstat

Answer

clamav

Question 5

A user wants to create a symbolic link to a file named 'original' in their home directory. Which command creates a symbolic link named 'link'?

Accepted Answer

ln -s original link. The 'ln -s' command creates a symbolic (soft) link. The syntax is 'ln -s ', so 'ln -s original link' creates a symlink named 'link' that points to 'original'. Without the -s flag, ln creates a hard link instead.

Answer

ln original link

Answer

ln -s link original

Answer

symlink original link

Question 6

An administrator wants to force a password change for user 'alice' on next login. Which command is appropriate?

Accepted Answer

passwd --expire alice. The `passwd --expire alice` command (equivalent to `passwd -e alice`) immediately expires alice's password by setting the shadow file's last-change date to 0, forcing a password change at her next login. This is the standard Linux mechanism for administrators to force a one-time password reset without disabling the account.

Answer

passwd -l alice

Answer

chage -l alice

Answer

usermod -f alice

Question 7

An administrator is troubleshooting a web server that is running under SELinux enforcing mode. The web content is located in a non-standard directory /webfiles. Using the standard SELinux context 'httpd_sys_content_t', the files are still inaccessible. Which command will properly set the context recursively and persist across relabels?

Accepted Answer

semanage fcontext -a -t httpd_sys_content_t '/webfiles(/.*)?' ; restorecon -Rv /webfiles. `semanage fcontext -a -t httpd_sys_content_t '/webfiles(/.*)?'` adds a file-context mapping to the SELinux policy database, ensuring the context survives a `restorecon` or filesystem relabel. The subsequent `restorecon -Rv /webfiles` applies that context recursively to the directory. Without the `semanage` entry, `restorecon` alone would revert to the default context (often `default_t`), which is not accessible by httpd.

Answer

chcon -R -t httpd_sys_content_t /webfiles

Answer

setenforce 0

Answer

restorecon -Rv /webfiles

Question 8

An administrator needs to add a script to be executed daily. The script is placed at /etc/cron.daily/myscript. After placing the script, it does not run. Based on the exhibit, what is the most likely issue?

Accepted Answer

The script is not executable. Scripts placed in /etc/cron.daily/ are executed by run-parts, which requires files to have the executable bit set. Without the execute permission (e.g., chmod +x), the script is skipped entirely, even if it is owned correctly and the cron daemon is active.

Answer

The script is owned by the wrong user

Answer

The cron daemon is not running

Answer

The script is not listed in /etc/crontab

Answer

Anacron is not installed

Question 9

Which TWO of the following are valid methods for debugging a Bash script? (Choose TWO.)

Accepted Answer

Run the script with 'bash -x script.sh'. Running 'bash -x script.sh' enables an execution trace that prints each command and its arguments to stderr before executing it, which is a standard debugging method for Bash scripts. Option C is correct because adding 'set -x' at the start of the script achieves the same trace output, but from within the script itself, allowing granular control over which sections are traced.

Answer

Add 'set -r' to restrict shell

Answer

Run the script with 'bash -d script.sh'

Answer

Add 'set -n' to check syntax

Question 10

A system administrator wants to schedule a script to run every Monday at 3 AM. Which cron entry is correct?

Accepted Answer

0 3 * * 1 /path/to/script.sh. The cron syntax for 'at 3 AM every Monday' is minute 0, hour 3, day-of-month *, month *, and day-of-week 1 (where 0 and 7 both represent Sunday, and 1 represents Monday). This matches the required schedule exactly.

Answer

0 3 1 * * /path/to/script.sh

Answer

3 0 * * 1 /path/to/script.sh

Answer

0 3 * * 2 /path/to/script.sh