This LFCS practice question tests your understanding of essential commands. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
To check the disk usage of the /var/log directory in a human-readable format, which command is appropriate?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "which command"
Why it matters: Tests specific CLI syntax. Recall the exact command and its required context — near-synonyms and partial matches are common distractors.
du -sh /var/log
du -sh gives a summary of the total disk usage for the specified directory.
ls -lh /var/log
Why wrong: ls lists individual files and directories, not the total disk usage of a directory.
df -h /var/log
Why wrong: df reports filesystem usage, not directory usage.
fdisk -l /var/log
Why wrong: fdisk is used to manipulate disk partition tables.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
du -sh /var/log
The `du -sh /var/log` command is correct because `du` (disk usage) estimates file and directory space usage, and the `-s` option summarizes the total for the specified directory, while `-h` prints sizes in human-readable format (e.g., K, M, G). This directly answers the requirement to check disk usage of the /var/log directory in a human-readable form.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
du -sh /var/log
Why this is correct
du -sh gives a summary of the total disk usage for the specified directory.
Clue confirmation
The clue word "which command" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
ls -lh /var/log
Why it's wrong here
ls lists individual files and directories, not the total disk usage of a directory.
df -h /var/log
Why it's wrong here
df reports filesystem usage, not directory usage.
fdisk -l /var/log
Why it's wrong here
fdisk is used to manipulate disk partition tables.
Common exam traps
The trap here is that candidates confuse `du` (directory usage) with `df` (filesystem usage), or mistakenly think `ls -lh` shows total directory size, when in fact `ls` only lists individual file sizes without summing subdirectory contents.
Detailed technical explanation
The `du` command works by traversing the directory tree and summing the sizes reported by the `stat` system call for each file, including metadata blocks (though `-h` only affects output formatting). A subtle behavior is that `du` by default counts apparent sizes, but with `--apparent-size` it can show logical sizes; the `-s` flag avoids listing subdirectories individually, which is critical for a clean summary. In real-world scenarios, `du -sh` is often used to identify large directories for cleanup, such as log rotation in /var/log, where `df` would be misleading because it shows filesystem-level usage, not per-directory consumption.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A practitioner preparing for the LFCS exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Essential Commands — study guide chapter
Learn the concepts, then practise the questions
Essential Commands practice questions
Targeted practice on this topic area only
All LFCS questions
513 questions across all exam domains
Linux Foundation Certified System Administrator LFCS study guide
Full concept coverage aligned to exam objectives
LFCS practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Practise LFCS questions linked to User and Group Management.
Practise LFCS questions linked to Operation of Running Systems.
Practise LFCS questions linked to Essential Commands.
Practise LFCS questions linked to Networking.
Practise LFCS questions linked to Service Configuration.
Practise LFCS questions linked to Storage Management.
Practise LFCS questions linked to LFCS fundamentals.
Practise LFCS questions linked to LFCS scenario.
Practise LFCS questions linked to LFCS troubleshooting.
Practice this exam
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Essential Commands — This question tests Essential Commands — Read the scenario before looking for a memorised answer..
The correct answer is: du -sh /var/log — The `du -sh /var/log` command is correct because `du` (disk usage) estimates file and directory space usage, and the `-s` option summarizes the total for the specified directory, while `-h` prints sizes in human-readable format (e.g., K, M, G). This directly answers the requirement to check disk usage of the /var/log directory in a human-readable form.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Yes — watch for: "which command". Tests specific CLI syntax. Recall the exact command and its required context — near-synonyms and partial matches are common distractors.
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Last reviewed: Jun 25, 2026
This LFCS practice question is part of Courseiva's free Linux Foundation certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the LFCS exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.