XK0-006 System Management — 100 Questions

Question 1

An administrator wants to find all files in the current directory tree that are larger than 100 MB and have the .log extension. Which find command will accomplish this?

Accepted Answer

find . -name '*.log' -size +100M. Find . -name '*.log' -size +100M. This command searches recursively from the current directory (.) for files with names matching '*.log' (-name '*.log') and with size greater than 100 MB (-size +100M). Option B is incorrect because the size syntax +100MB is wrong; the correct suffix is M for megabytes. Option C uses -size -100M which finds files smaller than 100 MB. Option D uses -type f (files only) but does not filter by .log extension, so it would include all files larger than 100 MB regardless of extension.

Answer

find . -name '*.log' -size +100MB

Answer

find . -name '*.log' -size -100M

Answer

find . -type f -size +100M

Question 2

An administrator needs to grant read and write access to the 'developers' group on a directory while preserving existing permissions for the owner and others. Which TWO commands can be used to modify ACLs? (Choose two.)

Accepted Answer

setfacl -m u:developers:rw /dir. setfacl is used to modify ACLs on files and directories. The -m option adds or modifies an ACL entry. Option C uses the user flag (u:) to set permissions for a user named 'developers', which can be valid if a user with that name exists and the intent is to grant access to that user. Option E correctly uses the group flag (g:) to grant read-write access to the 'developers' group. Both commands modify ACLs, while chmod changes standard permissions, getfacl only displays ACLs, and -x removes ACL entries.

Answer

chmod g+rw /dir

Answer

getfacl /dir

Answer

setfacl -x g:developers /dir

Question 3

A technician needs to replace the string 'oldhost' with 'newhost' in the file /etc/hostname. Which sed command will perform this change in-place?

Accepted Answer

sed -i '/oldhost/d' /etc/hostname. Uses 's/oldhost/newhost/g' with -i to perform a global in-place substitution, directly replacing 'oldhost' with 'newhost' as required. Option A uses 'd' to delete lines containing 'oldhost', which removes the old hostname but does not add the new one, thus failing to perform the replacement specified in the stem. Therefore, only option C correctly implements the string replacement.

Answer

sed 'y/oldhost/newhost/' /etc/hostname

Answer

sed 's/oldhost/newhost/g' /etc/hostname

Question 4

A system administrator needs to view the last 15 lines of a log file that is constantly being updated. Which TWO commands can be used to achieve this? (Choose two.)

Accepted Answer

cat -n /var/log/syslog | tail -15. tail -n 15 directly outputs the last 15 lines of the file. cat -n /var/log/syslog | tail -15 numbers all lines then shows the last 15, which also works. tail -f shows the last 10 lines by default and follows new content, so it does not specifically show the last 15 lines as required.

Answer

tail -f /var/log/syslog

Answer

head -n 15 /var/log/syslog

Answer

less +15 /var/log/syslog

Question 5

A Linux administrator needs to locate all files in the /var directory that have been modified within the last 30 minutes and are larger than 10MB. Which command accomplishes this task?

Accepted Answer

find /var -mmin -30 -size +10M. The find command with -mmin and -size options can locate files based on modification time and size. -mmin -30 finds files modified less than 30 minutes ago, and -size +10M finds files larger than 10MB.

Answer

find /var -mmin 30 -size +10M

Answer

locate /var -mmin -30 -size +10M

Answer

find /var -mtime -30 -size +10M

Question 6

A user reports that a script in /home/user/script.sh fails to execute. The output of 'ls -l script.sh' is '-rw-r--r-- 1 user user 1024 Apr 1 10:00 script.sh'. Which command should be used to make the script executable for all users?

Accepted Answer

chmod a+x script.sh. The file is currently not executable (rw-r--r--). To add execute permission for all users, use chmod a+x or chmod +x.

Answer

chmod 644 script.sh

Answer

chmod u+x script.sh

Answer

chmod 755 script.sh

Question 7

A system administrator needs to set the umask so that newly created files have permissions of 644 and directories have permissions of 755. Which umask value should be set?

Accepted Answer

0022. Default base permissions are 666 for files and 777 for directories. To get 644 (rw-r--r--) for files: 666 - 644 = 022. To get 755 (rwxr-xr-x) for directories: 777 - 755 = 022. So umask 022 works for both.

Answer

0222

Answer

000

Answer

077

Question 8

An administrator wants to grant a specific user, 'jdoe', read and write access to a file that is owned by root:root with permissions 640. The administrator does not want to change the file's owner or group. Which approach should be used?

Accepted Answer

Use setfacl -m u:jdoe:rw file. ACLs allow granting permissions to a specific user without changing the file's owner or group. setfacl -m u:jdoe:rw file sets read-write ACL for user jdoe.

Answer

Change file owner to jdoe

Answer

Use chmod o+rw file

Answer

Add jdoe to the root group

Question 9

A user needs to view the first 15 lines of a large log file. Which command is most appropriate?

Accepted Answer

head -n 15 filename. head -n 15 filename displays the first 15 lines of a file.

Answer

cat filename | head -n 15

Answer

less -N 15 filename

Answer

tail -n 15 filename

Question 10

A Linux administrator wants to search for all occurrences of the word 'ERROR' in log files under /var/log, ignoring case, and also print the line numbers. Which command should be used?

Accepted Answer

grep -rin 'ERROR' /var/log. grep -rin 'ERROR' /var/log searches recursively, ignores case, and prints line numbers. -i for case-insensitive, -n for line numbers, -r for recursive.

Answer

grep -vi 'ERROR' /var/log

Answer

grep -rn 'ERROR' /var/log

Answer

find /var/log -name '*ERROR*'

Question 11

An administrator needs to replace all occurrences of 'oldhost' with 'newhost' in the configuration file /etc/hosts. Which command will perform the replacement and save the changes directly to the file?

Accepted Answer

sed -i 's/oldhost/newhost/g' /etc/hosts. The `-i` flag (in-place editing) tells `sed` to write the changes directly back to the file specified. Without `-i`, `sed` only prints the modified output to stdout and does not alter the original file. The substitution command `s/oldhost/newhost/g` performs a global replacement of all occurrences of 'oldhost' with 'newhost' on each line.

Answer

sed 's/oldhost/newhost/g' /etc/hosts

Answer

awk '{gsub(/oldhost/,"newhost")}1' /etc/hosts

Answer

grep -r 'oldhost' /etc/hosts | sed 's/oldhost/newhost/g'

Question 12

A process with PID 2345 is not responding. The administrator wants to force stop the process immediately. Which command should be used?

Accepted Answer

kill -9 2345. SIGKILL (signal 9) forcefully terminates a process. kill -9 2345 sends SIGKILL to PID 2345.

Answer

kill -1 2345

Answer

pkill -15 -f processname

Answer

kill -15 2345

Question 13

A service called 'myapp' fails to start automatically after a system reboot. The administrator wants to ensure the service starts at boot. Which systemctl command should be used?

Accepted Answer

systemctl enable myapp. The `systemctl enable myapp` command creates the necessary symlinks in the systemd unit configuration directories (typically `/etc/systemd/system/multi-user.target.wants/`) so that the `myapp` service is automatically started at boot. This is the correct approach because the question specifically asks to ensure the service starts after a reboot, not to start it immediately.

Answer

systemctl daemon-reload

Answer

systemctl start myapp

Answer

systemctl reenable myapp

Question 14

Which directory in the Linux filesystem contains essential user command binaries that are needed for booting and repairing the system?

Accepted Answer

/bin. /bin contains essential command binaries required for booting and recovery.

Answer

/usr/bin

Answer

/sbin

Answer

/opt

Question 15

An administrator needs to view the last 20 lines of the systemd journal for the 'sshd' service. Which command should be used?

Accepted Answer

journalctl -u sshd -n 20. journalctl -u sshd -n 20 shows the last 20 lines of the journal for the sshd unit.

Answer

systemctl status sshd | tail -20

Answer

journalctl -u sshd --since '1 hour ago'

Answer

journalctl -u sshd -f

Question 16

A system administrator needs to install a package from a local RPM file without resolving dependencies automatically. Which command should be used?

Accepted Answer

rpm -i package.rpm. The `rpm -i package.rpm` command installs the specified RPM package without automatically resolving dependencies. The `-i` flag stands for 'install' and, unlike `-U` (upgrade) or higher-level tools like `yum` or `dnf`, it does not attempt to fetch or satisfy missing dependencies from configured repositories. This is the correct choice when the requirement is to install a local RPM file while explicitly avoiding automatic dependency resolution.

Answer

rpm -U package.rpm

Answer

yum localinstall package.rpm

Answer

dnf install ./package.rpm

Question 17

A Linux administrator needs to display the amount of disk space used by each mounted filesystem. Which two commands can be used? (Choose two.)

Accepted Answer

du -h /. The question asks for two commands that display the amount of disk space used by each mounted filesystem. Both df -h (option E) and du -h / (option A) serve this purpose. df -h shows disk space usage for all mounted filesystems in human-readable format. du -h / shows disk usage for the root directory, which is a mounted filesystem; while du is typically used for directory-level usage, the root directory corresponds to the root filesystem, so it effectively displays the disk space used by that filesystem. mount | column -t (option B) lists mount points and options, not space usage. lsblk (option C) lists block devices, not filesystem space. fdisk -l (option D) displays partition tables, not filesystem usage. Therefore, options A and E are correct.

Answer

mount | column -t

Answer

lsblk

Answer

fdisk -l

Question 18

An administrator wants to change the runlevel/target to a state where only a minimal set of processes is running, and network services are disabled. Which two systemd targets achieve this? (Choose two.)

Accepted Answer

rescue.target. (rescue.target) is correct because it boots the system into a single-user mode with a minimal set of processes and no network services, allowing administrative tasks like filesystem repairs. Option E (emergency.target) is correct because it starts an even more minimal environment with only a root shell on the console, also disabling network services. Both targets satisfy the requirement of minimal processes and disabled networking.

Answer

graphical.target

Answer

poweroff.target

Answer

multi-user.target

Question 19

A user wants to create a hard link to a file. Which three conditions must be true for a hard link to be created successfully? (Choose three.)

Accepted Answer

The source and link must be on the same filesystem.. Hard links cannot span filesystems, cannot link to directories (except by root with special options), and the target must exist. They share the same inode.

Answer

The source file must have the SUID bit set.

Answer

The link must have the same name as the source.

Question 20

A Linux administrator needs to view the last 10 lines of a log file named 'syslog'. Which command should be used?

Accepted Answer

tail -10 syslog. The 'tail' command outputs the last lines of a file; by default it shows 10 lines.

Answer

cat syslog

Answer

head -10 syslog

Answer

less syslog