Quick Answer
The correct commands are `zless`, `zmore`, and `zcat`, as all three allow you to view a compressed .gz file without permanently decompressing it. These utilities work by decompressing the file on the fly and piping the output to a pager or standard output, leaving the original `file.gz` untouched on disk. On the LFCS exam, this tests your understanding of the `z*` family of commands, which are often confused with their uncompressed counterparts—a common trap is assuming `less` or `more` can directly read gzip files, but they cannot. Remember that `zcat` sends output to the terminal (like `cat`), `zless` provides scrollable viewing (like `less`), and `zmore` pages through content (like `more`). A handy memory tip: think of the prefix "z" as "zipped," so `zcat`, `zless`, and `zmore` are simply the zipped versions of `cat`, `less`, and `more`.
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.
Which THREE of the following commands can be used to view the contents of a compressed file named 'file.gz' without permanently decompressing it? (Choose exactly three.)
gzip file.gz
Why wrong: Compresses files.
zmore file.gz
Correct: displays with more.
gunzip file.gz
Why wrong: Decompresses permanently.
zcat file.gz
Correct: decompresses to stdout.
zless file.gz
Correct: displays with less.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
zmore file.gz
Option B is correct because `zmore` is a utility that allows you to view the contents of a compressed file (such as `file.gz`) page by page without permanently decompressing it. It internally decompresses the file on the fly and pipes the output through `more`, making it ideal for inspecting large compressed files without modifying the original archive.
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.
gzip file.gz
Why it's wrong here
Compresses files.
zmore file.gz
Why this is correct
Correct: displays with more.
Related concept
Read the scenario before looking for a memorised answer.
gunzip file.gz
Why it's wrong here
Decompresses permanently.
zcat file.gz
Why this is correct
Correct: decompresses to stdout.
Related concept
Read the scenario before looking for a memorised answer.
zless file.gz
Why this is correct
Correct: displays with less.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
The trap here is that candidates mistakenly think `gunzip` or `gzip` can be used to view file contents without permanent decompression, confusing compression/decompression commands with viewing utilities like `zcat`, `zmore`, and `zless`.
Detailed technical explanation
Under the hood, `zcat`, `zmore`, and `zless` all use the same underlying mechanism: they invoke `gzip -dc` to decompress the file to stdout, then pipe the output to a pager (`cat`, `more`, or `less` respectively). A subtle behavior is that `zcat` may fail if the compressed file is not in gzip format (e.g., it expects the magic bytes `1f 8b`), while `zless` and `zmore` are more forgiving and can handle other compression types via `less`'s built-in support. In real-world scenarios, system administrators often use `zless` to quickly inspect log files that have been rotated and compressed, avoiding the need to decompress large files on disk.
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.
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FAQ
Essential Commands — This question tests Essential Commands — Read the scenario before looking for a memorised answer..
The correct answer is: zmore file.gz — Option B is correct because `zmore` is a utility that allows you to view the contents of a compressed file (such as `file.gz`) page by page without permanently decompressing it. It internally decompresses the file on the fly and pipes the output through `more`, making it ideal for inspecting large compressed files without modifying the original archive.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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 →
Same concept, more angles
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A user needs to view the contents of a compressed log file /var/log/syslog.gz without first decompressing it. Which command should they use?
easyWhy A: Option A is correct because `zcat` is specifically designed to read the contents of gzip-compressed files without permanently decompressing them. It decompresses the data on the fly and sends the output to stdout, allowing the user to view the log file's contents directly from the terminal.
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Last reviewed: Jun 11, 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.
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