XK0-006 System Management Practice Test 14 — 15 Questions

Question 1

A Linux administrator needs to permanently set the system-wide umask to 027 for all users on a production server. The administrator edits /etc/profile and adds the line 'umask 027'. After rebooting, a user logs in and runs 'umask', which returns 0022. Which of the following is the most likely reason the setting did not take effect?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

The user's shell configuration file, such as ~/.bashrc or ~/.profile, overrides the umask set in /etc/profile.. The umask is set per process and inherited. System-wide defaults in /etc/profile apply to login shells, but user-specific files like ~/.bashrc or ~/.profile are sourced later and can override the umask. Since the user's umask returned 0022, it indicates a user-level configuration is taking precedence. To enforce a system-wide umask, administrators must ensure user files do not override it or use mechanisms like pam_umask.

Answer

The umask command must be run with sudo to affect all users.

Answer

The umask value must be set in /etc/login.defs to apply system-wide.

Answer

The system needs to be rebooted for changes to /etc/profile to take effect.

Question 2

A Linux administrator needs to configure a system to automatically mount an NFS share at /mnt/data during boot. The NFS server is 192.168.1.100 exporting /export/data. Which file should the administrator edit to add the appropriate entry?

Accepted Answer

/etc/fstab. To ensure an NFS share is mounted automatically at boot, the administrator must add an entry to /etc/fstab. This file contains static filesystem information that systemd uses to generate mount units. The entry includes the server export, local mount point, filesystem type, and options. Other files like /etc/mtab or /etc/nfs.conf serve different purposes and do not control persistent mounts.

Answer

/etc/nfs.conf

Answer

/etc/mtab

Answer

/etc/exports

Question 3

A Linux administrator needs to check the available disk space on all mounted filesystems in a human-readable format. Which command should the administrator use?

Accepted Answer

df -h. df -h is the correct command because it reports filesystem disk space usage and free space for all mounted filesystems in human-readable units. The -h flag converts sizes to GB, MB, or KB as appropriate, making the output easy to interpret. Other commands either show file sizes, partition tables, or block device topology, not free space.

Answer

fdisk -l

Answer

du -h

Answer

lsblk

Question 4

A Linux administrator is troubleshooting a system that is running out of disk space on the root filesystem. The administrator needs to identify which directories are consuming the most space. Which TWO commands can be used to find the largest directories? (Choose two.)

Accepted Answer

ncdu /. The commands du -sh /* | sort -rh | head -n 10 and ncdu / are both effective for identifying the largest directories. The du pipeline provides a quick text-based summary, while ncdu offers an interactive interface for exploration. Both directly address the need to find space-consuming directories.

Answer

ls -lR /

Answer

df -h

Answer

find / -type d -size +100M

Question 5

An administrator notices that the /var partition on a production server is nearly full and wants to determine which subdirectories consume the most space before deleting anything. The administrator has root privileges and wants a human-readable summary of each immediate subdirectory under /var, one line per directory. Which command accomplishes this?

Accepted Answer

du -sh /var/*. To see which directories under /var consume the most space, du with -s and -h summarizes each argument passed via shell glob expansion, producing one human-readable line per immediate subdirectory. This gives an actionable ranking of space consumers. Filesystem-level tools like df and metadata listings like ls do not aggregate directory totals, so they cannot answer the question.

Answer

df -h /var

Answer

find /var -size +100M

Answer

ls -lhR /var

Question 6

A Linux administrator is troubleshooting a systemd service named 'webapp.service' that fails to start. The administrator runs 'systemctl status webapp.service' and sees that the service is in a failed state. Which TWO commands will provide additional diagnostic information about why the service failed? (Choose two.)

Accepted Answer

journalctl -u webapp.service. To diagnose why a systemd service failed, administrators need access to logs and error messages. journalctl -u webapp.service filters the journal for that unit, showing its output and systemd's messages. journalctl -xe shows recent system-wide errors with explanations, which often include the service failure. Commands like systemctl cat, show, and list-dependencies are for configuration and dependency inspection, not runtime diagnostics.

Answer

systemctl show webapp.service

Answer

systemctl cat webapp.service

Answer

systemctl list-dependencies webapp.service

Question 7

An administrator manages a server with several systemd services. A service named reportgen.service must not start until another service named dbengine.service is fully active, and reportgen should be stopped automatically if dbengine stops. Which directive combination in the reportgen.service unit file achieves this ordering and dependency?

Accepted Answer

After=dbengine.service and Requires=dbengine.service. Ordering and dependency are separate concerns in systemd. After= controls sequence, ensuring reportgen starts once dbengine is active, while Requires= creates a hard dependency so reportgen stops if dbengine stops. Using After= with Requires= satisfies both requirements. Wants= is too weak to force the stop behavior, and Before= would invert the required startup order.

Answer

After=dbengine.service and Wants=dbengine.service

Answer

Before=dbengine.service and Wants=dbengine.service

Answer

Requires=dbengine.service and Before=dbengine.service

Question 8

A Linux administrator notices that the /home directory is running low on space. They need to identify which user directories are consuming the most disk space. Which command will display the total disk usage of each immediate subdirectory under /home, in human-readable format, sorted by size?

Accepted Answer

du -sh /home/* | sort -h. The du command with -s and -h summarizes each specified directory in human-readable units; using a glob for immediate subdirectories and piping to sort -h orders them by size. This gives a clear ranking of which user directories consume the most space, directly addressing the low-space issue. Other tools either report filesystem-level totals or list files without per-directory aggregation.

Answer

ls -lS /home

Answer

df -h /home

Answer

find /home -type f -size +100M

Question 9

A Linux administrator is preparing a new server that uses systemd-boot as the boot loader. The administrator wants to verify the current boot loader entries and their order. Which command should the administrator run?

Accepted Answer

bootctl list. The bootctl list command displays all systemd-boot entries and their sequence, which is exactly what the administrator needs to verify the boot loader configuration on a system using systemd-boot. The other tools either manage different boot loaders (GRUB), interact with UEFI firmware (efibootmgr), or assume systemd-boot is a service (systemctl), so they do not provide the required information.

Answer

efibootmgr -v

Answer

grub-mkconfig -o /boot/grub/grub.cfg

Answer

systemctl status systemd-boot

Question 10

A junior administrator needs to change the ownership of the file /var/www/html/index.html from user 'www-data' to user 'apache' and group 'apache'. Which command will accomplish this?

Accepted Answer

chown apache:apache /var/www/html/index.html. The chown command with user:group syntax changes both the owner and group of a file. Specifying apache:apache sets the owner and group to apache, fulfilling the requirement. Other commands either modify permissions, change only the group, or modify user account properties rather than file ownership.

Answer

usermod -g apache www-data /var/www/html/index.html

Answer

chmod apache:apache /var/www/html/index.html

Answer

chgrp apache /var/www/html/index.html

Question 11

A Linux server is configured to use systemd. The administrator wants to ensure that a custom service named 'app.service' starts automatically at boot, even if it has been manually stopped. Which command should be used?

Accepted Answer

systemctl enable app.service. The correct answer is the command that creates the necessary symbolic links for the service to start automatically at boot. This is done with systemctl enable. The other commands either start the service now, reset enablement, or apply presets, none of which ensure persistent automatic startup.

Answer

systemctl start app.service

Answer

systemctl preset app.service

Answer

systemctl reenable app.service

Question 12

A Linux administrator needs to create a new user account named 'jsmith' with a home directory /home/jsmith and the default shell /bin/bash. Which command should the administrator use?

Accepted Answer

useradd -m -s /bin/bash jsmith. The correct command is useradd -m -s /bin/bash jsmith, which creates the user, makes the home directory, and sets the login shell to /bin/bash. This is the most direct and portable way to create a user with specific attributes. Other commands either modify existing users, set passwords, or are interactive and less precise.

Answer

passwd jsmith

Answer

usermod -aG jsmith

Answer

adduser jsmith

Question 13

An administrator needs to monitor a service's log output and wants systemd to capture the output of a specific service unit into the journal, tagged so it can be filtered by the unit name. The administrator also wants to limit how much disk space the journal may consume so it does not fill the root filesystem. Which configuration accomplishes both goals?

Accepted Answer

Set SystemMaxUse in /etc/systemd/journald.conf and ensure the service logs to the journal via StandardOutput=journal in its unit file. Capturing a service's output in the journal with unit tagging requires the unit to send output to the journal, and journald limits total disk usage through SystemMaxUse in journald.conf. Filtering by unit then works with journalctl -u. Disabling storage, redirecting output to files, or limiting only the runtime journal fails to both capture and cap the data as required.

Answer

Set RuntimeMaxUse in journald.conf and add StandardOutput=file:/var/log/report.log to the service unit

Answer

Set Storage=none in journald.conf and add StandardOutput=syslog to the service unit

Answer

Set MaxLevelStore in journald.conf and add StandardError=null to the service unit

Question 14

A Linux administrator is troubleshooting a system that fails to mount the root filesystem during boot, dropping to an emergency shell. The administrator suspects that a recently added entry in /etc/fstab is incorrect. Which of the following commands should be used to verify the syntax and mountability of all entries in /etc/fstab without actually mounting them?

Accepted Answer

findmnt --verify. The findmnt --verify command is designed to validate the syntax and mountability of entries in /etc/fstab and related files without mounting them. It checks for common errors such as invalid device names, duplicate mount points, and unsupported options. This allows the administrator to identify problematic entries before attempting a reboot, avoiding a boot failure. Other commands either mount the filesystems or perform unrelated checks.

Answer

fsck -A

Answer

mount -a

Answer

blkid

Question 15

A Linux administrator is troubleshooting a server that fails to mount a filesystem listed in /etc/fstab during boot, causing the system to drop into emergency mode. The administrator wants to prevent the system from entering emergency mode if this particular mount fails, while still attempting to mount it. Which fstab option should be added to the mount entry?

Accepted Answer

nofail. The nofail option in /etc/fstab instructs systemd to ignore mount failures for that entry, allowing the boot to proceed even if the device is unavailable. This prevents the system from dropping into emergency mode. The other options either do not affect error handling or are already implied by defaults, so they do not provide the needed resilience.

Answer

nouser

Answer

auto

Answer

defaults