20+ practice questions focused on Essential Commands — one of the most tested topics on the Linux Foundation Certified System Administrator LFCS exam. Each question includes a detailed explanation so you learn why the right answer is correct.
Start Essential Commands PracticeAn administrator wants to find all files larger than 100MB in the /home directory. Which two commands or command sequences achieve this? (Choose two.)
Explanation: `-size +100M` matches files larger than 100 megabytes (where M stands for mebibytes, 1024*1024 bytes). Option D is correct because `-size +102400k` matches files larger than 100 megabytes (since 100*1024 = 102400 kilobytes). Option B is incorrect because `-size +100000000c` matches files larger than approximately 95.4 MB (100,000,000 bytes), not 100 MB. Option C is incorrect because `MB` is not a valid size suffix in find. Option E is incorrect because it omits the `+` sign, matching files exactly 100 MB rather than larger than 100 MB.
Which TWO commands can be used to change the ownership of a file to a specific user and group? (Select two.)
Explanation: The `chown alice:staff file.txt` command changes both the user owner to `alice` and the group owner to `staff` in a single operation. Option C is correct because `chgrp staff file.txt` changes only the group ownership of the file to `staff`. Option D is incorrect because `usermod -G staff alice` modifies the group membership of the user `alice`, not the ownership of any file.
A user reports that a script fails with 'Permission denied' when executed. The script has permissions -rw-r--r-- and is owned by the user. Which command should the user run to make the script executable for the owner only?
Explanation: The script currently has permissions `-rw-r--r--`, meaning the owner has read and write but not execute permission. The `chmod u+x` command adds the execute permission for the owner only, which is exactly what the user needs to run the script without affecting group or others.
A system administrator needs to find all files in /var/log that have been modified in the last 7 days. Which command accomplishes this?
Explanation: The `find` command with `-mtime -7` searches for files whose modification time (content change) is less than 7 days ago, which matches the requirement of 'modified in the last 7 days'. The `-type f` restricts the search to regular files, and `/var/log` is the target directory.
An administrator wants to ensure that a background process continues running after logout. Which command should be used to start the process?
Explanation: `nohup` allows a process to ignore the SIGHUP signal that is sent to background processes when the parent shell exits, ensuring it continues running after logout. The `&` places the command in the background, and `nohup` redirects output to `nohup.out` by default, making it the standard way to run a process immune to hangups.
+15 more Essential Commands questions available
Practice all Essential Commands questions1. Baseline your knowledge
Start with 10 questions to gauge your current understanding of Essential Commands. This tells you whether you need a concept refresher or just practice.
2. Review every explanation
For each question — right or wrong — read the full explanation. Understanding why an answer is correct is more valuable than knowing the answer itself.
3. Focus on exam traps
Essential Commands questions on the LFCS frequently use trap wording. Look for subtle differences in answers that test your precision, not just general knowledge.
4. Reach 80% consistently
Do repeated sessions until you score 80%+ three times in a row. Then move to mixed-mode practice to test cross-topic recall under realistic conditions.
The exact number varies per candidate. Essential Commands is tested as part of the Linux Foundation Certified System Administrator LFCS blueprint. Practicing with targeted Essential Commands questions ensures you can handle any format or difficulty that appears.
Yes. Courseiva provides free LFCS practice questions across all exam topics and domains. The platform includes topic-based practice, mock exams, missed-question review, bookmarked questions, and readiness tracking — no account required.
Difficulty is subjective, but Essential Commands is a high-priority exam concept tested in multiple ways — direct recall, scenario analysis, and command-output interpretation. Consistent practice is the best way to build confidence.
Launch a full Essential Commands practice session with instant scoring and detailed explanations.
Start Essential Commands Practice →