Q1. Which directory contains systemd unit files?
- A./etc/systemd
- B./lib/systemd
- C./usr/lib/systemd
- D.All of the above✓ Correct
Explanation: systemd looks for units in multiple directories with /etc taking precedence. Learn more.
CompTIA Linux+ Practice Questions: System Management
36 free, exam-style CompTIA Linux+ (XK0-006) practice questions covering System Management. Each question shows the correct answer and a clear explanation. Ready for the real thing? Take the full timed quiz below.
Q2. What does 'systemctl isolate multi-user.target' do?
- A.Reboot system
- B.Enter rescue mode
- C.Switch to non-graphical mode✓ Correct
- D.Shutdown services
Explanation: Changes system state to multi-user (non-GUI) target. Learn more.
Q3. What is the purpose of 'make modules_install' during kernel compilation?
- A.Compile kernel source
- B.Install kernel modules✓ Correct
- C.Update bootloader
- D.Configure kernel options
Explanation: Installs compiled modules to /lib/modules/<version>/. Learn more.
Q4. Which command shows kernel module dependencies?
- A.lsmod✓ Correct
- B.modinfo
- C.depmod
- D.modprobe
Explanation: lsmod displays loaded modules and dependencies. Learn more.
Q5. Which command refreshes systemd configuration?
- A.systemctl reload
- B.systemctl daemon-reload✓ Correct
- C.systemctl restart
- D.systemctl reexec
Explanation: daemon-reload reloads unit files after modification. Learn more.
Q6. What does 'chroot' do?
- A.Change root password
- B.Modify process root directory✓ Correct
- C.Check disk usage
- D.Repair filesystem
Explanation: chroot jail confines processes to a specific directory tree. Learn more.
Q7. Which directory holds temporary systemd mount units?
- A./etc/systemd/system
- B./run/systemd/system✓ Correct
- C./usr/lib/systemd/system
- D./var/lib/systemd
Explanation: /run contains transient runtime configuration. Learn more.
Q8. What is the purpose of 'at' command?
- A.Schedule recurring jobs
- B.Run commands once at a specific time✓ Correct
- C.List users
- D.Monitor system activity
Explanation: at executes commands once at a specified time. Learn more.
Q9. Which directory contains udev rules?
- A./etc/udev/rules.d✓ Correct
- B./lib/udev
- C./run/udev
- D./var/lib/udev
Explanation: Custom udev rules go in /etc/udev/rules.d/*.rules. Learn more.
Q10. What is the purpose of /etc/aliases?
- A.Email alias mapping✓ Correct
- B.Command aliases
- C.Network aliases
- D.User alias groups
Explanation: Used by sendmail/postfix for email forwarding. Learn more.
Q11. Which file defines cron jobs for all users?
- A./etc/crontab✓ Correct
- B./etc/cron.d/
- C./var/spool/cron/
- D./etc/anacrontab
Explanation: /etc/crontab is the system-wide crontab file. Learn more.
Q12. Which directory contains kernel header files?
- A./usr/src/linux-headers-*✓ Correct
- B./lib/modules
- C./boot
- D./etc/kernel
Explanation: Header files needed for compiling kernel modules. Learn more.
Q13. Which command shows GRUB menu during boot?
- A.Hold Shift✓ Correct
- B.Press Ctrl+C
- C.Type 'grub'
- D.Press F12
Explanation: Shift shows GRUB menu on UEFI systems; Esc on BIOS. Learn more.
Q14. Which file defines default runlevel in SysV init?
- A./etc/inittab✓ Correct
- B./etc/init.d
- C./etc/rc.local
- D./etc/runlevel
Explanation: inittab specifies default runlevel (replaced by systemd targets). Learn more.
Q15. What does 'ulimit -a' display?
- A.All user limits✓ Correct
- B.ARP table
- C.Active users
- D.Available memory
Explanation: Shows resource limits (CPU, memory, processes, etc.). Learn more.
Q16. Which file defines default GRUB boot parameters?
- A./boot/grub/grub.cfg
- B./etc/default/grub✓ Correct
- C./etc/grub.d/
- D./proc/cmdline
Explanation: /etc/default/grub is modified then grub-mkconfig generates grub.cfg. Learn more.
Q17. What does 'systemctl mask' do?
- A.Disable service
- B.Hide service logs
- C.Encrypt service config
- D.Prevent service from starting✓ Correct
Explanation: mask prevents accidental service activation via symlink to /dev/null. Learn more.
Q18. Which command lists all cron jobs for the current user?
- A.crontab -l✓ Correct
- B.cron list
- C.cat /etc/crontab
- D.ls /var/spool/cron
Explanation: crontab -l displays user's scheduled jobs. Learn more.
Q19. What is the purpose of the 'ldconfig' command?
- A.Configure LDAP
- B.Rebuild shared library cache✓ Correct
- C.List disk configurations
- D.Load kernel modules
Explanation: ldconfig updates links and cache for shared libraries. Learn more.
Q20. Which directory contains initramfs images?
- A./boot✓ Correct
- B./etc/initramfs
- C./lib/initramfs
- D./var/lib/initramfs
Explanation: initramfs stored in /boot with kernel images. Learn more.
Q21. Which command lists loaded kernel modules?
- A.lsmod✓ Correct
- B.modprobe
- C.insmod
- D.depmod
Explanation: lsmod shows currently loaded modules. Learn more.
Q22. What does 'systemctl enable' do?
- A.Start service now
- B.Enable auto-start at boot✓ Correct
- C.Reload service config
- D.Show service status
Explanation: Enables service to start at boot time. Learn more.
Q23. Which directory contains kernel modules?
- A./lib/modules✓ Correct
- B./etc/kernel
- C./usr/src/linux
- D./boot
Explanation: Modules stored in /lib/modules/<kernel-version>/. Learn more.
Q24. Which directory contains udev device rules?
- A./etc/udev/rules.d✓ Correct
- B./lib/udev
- C./run/udev
- D./usr/share/udev
Explanation: Custom udev rules go in /etc/udev/rules.d/*.rules. Learn more.
Q25. Which file defines NTP servers for chronyd?
- A./etc/chrony.conf✓ Correct
- B./etc/ntp.conf
- C./etc/systemd/timesyncd.conf
- D./etc/ntp.drift
Explanation: chronyd uses chrony.conf for NTP configuration. Learn more.
Q26. What is the purpose of 'systemd-inhibit'?
- A.Prevent system sleep during operations✓ Correct
- B.Block user logins
- C.Disable services
- D.Encrypt systemd journals
Explanation: Temporarily inhibits power/sleep states. Learn more.
Q27. Which file defines keyboard layout settings?
- A./etc/vconsole.conf
- B./etc/X11/xorg.conf
- C./etc/default/keyboard
- D.All of the above✓ Correct
Explanation: Multiple files control keyboard settings depending on environment. Learn more.
Q28. What does 'grub2-mkconfig -o /boot/grub2/grub.cfg' do?
- A.Backup GRUB config
- B.Generate new GRUB config✓ Correct
- C.Overwrite kernel parameters
- D.Install GRUB bootloader
Explanation: Rebuilds GRUB configuration file from templates. Learn more.
Q29. Which systemd command shows failed units?
- A.systemctl --failed✓ Correct
- B.journalctl --vacuum
- C.useradd -m
- D.ip route add
Explanation: systemctl --failed lists units that are currently in a failed state. Learn more.
Q30. Which systemd target is comparable to a multi-user text mode without a graphical interface?
- A.multi-user.target✓ Correct
- B.graphical.target
- C.rescue.target only
- D.poweroff.target
Explanation: multi-user.target provides multi-user services without requiring a graphical desktop. Learn more.
Q31. Which command creates a new user with a home directory on many Linux distributions?
- A.useradd -m username✓ Correct
- B.chmod -m username
- C.grep -m username
- D.mkfs -m username
Explanation: useradd -m creates a user and home directory on systems where useradd is used directly. Learn more.
Q32. Which command displays loaded kernel modules?
- A.lsmod✓ Correct
- B.lsblk
- C.lscpu
- D.lsusb only
Explanation: lsmod lists modules currently loaded into the Linux kernel. Learn more.
Q33. Which systemd command enables a service to start automatically at boot?
- A.systemctl enable service✓ Correct
- B.systemctl mask service only
- C.journalctl -u service
- D.hostnamectl set-hostname service
Explanation: systemctl enable creates the boot-time links needed for a service to start automatically. Learn more.
Q34. Which command displays CPU architecture and model details?
- A.lscpu✓ Correct
- B.lsmem -d
- C.free -c
- D.uname -p only
Explanation: lscpu displays CPU architecture, cores, threads, and model information. Learn more.
Q35. Which command rebuilds an initramfs image on many RPM-based Linux distributions?
- A.ldconfig -f
- B.depmod --unload
- C.systemctl preset-all
- D.dracut -f✓ Correct
Explanation: dracut creates initramfs images, and -f overwrites the existing image when drivers or early-boot configuration change. Learn more.
Q36. Which command loads a kernel module and automatically resolves its module dependencies?
- A.insmod --nodeps MODULE
- B.lsmod MODULE
- C.sysctl -p MODULE
- D.modprobe MODULE✓ Correct
Explanation: modprobe uses the module dependency database to load the requested module and any required dependencies. Learn more.