XK0-005 System Management — Timed 100 Questions

Question 1

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 2

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 3

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 4

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 5

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 6

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 7

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. Option D is correct because 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 8

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 9

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 10

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 11

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 12

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 13

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

df -h. df -h displays disk space usage in human-readable format. du -h / shows disk usage for directories but not per filesystem. lsblk shows block devices, not usage. fdisk is for partitioning. mount shows mount points but not space.

Answer

du -h /

Answer

mount | column -t

Answer

lsblk

Answer

fdisk -l

Question 14

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. Option B (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 15

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 16

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

Question 17

A technician notices a script fails to execute because the user does not have permission. The script currently has permissions 644. The technician needs to add execute permission for the owner only. Which command accomplishes this?

Accepted Answer

chmod u+x script.sh. The script currently has permissions 644, meaning the owner has read/write (6), group has read (4), and others have read (4). The requirement is to add execute permission for the owner only. The command `chmod u+x script.sh` adds (+) execute (x) permission to the user (u) — the owner — without affecting group or others. This is the precise and minimal command to achieve the goal.

Answer

chmod a+x script.sh

Answer

chmod 755 script.sh

Answer

chmod 744 script.sh

Question 18

An administrator wants to find all files in /var/log that have been modified within the last 2 days and have a .log extension. Which command should be used?

Accepted Answer

find /var/log -type f -mtime -2 -name "*.log". The find command with -mtime -2 finds files modified less than 2 days ago, and -name '*.log' matches the extension.

Answer

find /var/log -mtime 2 -name *.log

Answer

locate --mtime -2 *.log /var/log

Answer

ls -la /var/log | grep "\.log$" | head -20

Question 19

A system administrator wants to ensure a service starts automatically at boot and also starts immediately without rebooting. Which systemctl commands should be used?

Accepted Answer

systemctl start service && systemctl enable service. systemctl enable sets the service to start at boot, and systemctl start starts it immediately.

Answer

systemctl enable service && systemctl restart service

Answer

systemctl start --now service

Answer

systemctl enable --now service

Question 20

Which command displays the disk usage of files and directories in a human-readable format (e.g., KB, MB)?

Accepted Answer

du -h. The `du -h` command (disk usage with human-readable flag) recursively summarizes disk usage for files and directories, appending size suffixes like K, M, G for kilobytes, megabytes, and gigabytes. This directly matches the question's requirement to display disk usage in a human-readable format.

Answer

df -h

Answer

ls -lh

Answer

stat -h