This PT0-002 practice question tests your understanding of tools and code analysis. 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.
A penetration tester is writing a Bash script to enumerate users from the /etc/passwd file on a compromised Linux system. Which command will efficiently print only the usernames?
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.
Cut splits lines at ':' and outputs field 1 (the username). This is simple and efficient.
B
awk -F: '{print $1}' /etc/passwd
Why wrong: While awk also works, cut is more lightweight for this specific task; however, the question asks for the 'most efficient' and cut is the standard choice.
C
grep -o '^[^:]*' /etc/passwd
Why wrong: This uses a regular expression to match the beginning of the line up to the first colon, but grep is typically slower for field extraction.
D
sed 's/:.*//' /etc/passwd
Why wrong: Sed removes everything after the first colon, but it's less intuitive and slower than cut for this purpose.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
cut -d: -f1 /etc/passwd
Option A is correct because the `cut` command with `-d:` sets the field delimiter to colon (the separator in /etc/passwd) and `-f1` extracts the first field, which is the username. This is the most efficient and straightforward method for this specific task, as it directly isolates the username column without pattern matching or processing overhead.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
cut -d: -f1 /etc/passwd
Why this is correct
Cut splits lines at ':' and outputs field 1 (the username). This is simple and efficient.
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.
✗
awk -F: '{print $1}' /etc/passwd
Why it's wrong here
While awk also works, cut is more lightweight for this specific task; however, the question asks for the 'most efficient' and cut is the standard choice.
✗
grep -o '^[^:]*' /etc/passwd
Why it's wrong here
This uses a regular expression to match the beginning of the line up to the first colon, but grep is typically slower for field extraction.
✗
sed 's/:.*//' /etc/passwd
Why it's wrong here
Sed removes everything after the first colon, but it's less intuitive and slower than cut for this purpose.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often overthink the problem and choose `awk` or `grep` because they are more familiar with them for text processing, overlooking that `cut` is the simplest and most efficient tool for fixed-delimiter column extraction.
Detailed technical explanation
How to think about this question
The `/etc/passwd` file uses a colon (`:`) as the field delimiter, with the username as the first field (field 1). The `cut` command is optimized for fixed-delimiter field extraction and operates in a single pass without invoking a full interpreter, making it the fastest tool for this job. In real-world penetration testing, minimizing command execution time and resource usage is critical when running scripts on compromised systems to avoid detection or performance impact.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A security analyst at a medium-sized enterprise encounters this scenario during an investigation or architecture review. The correct answer reflects best practice for the specific threat or control described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Security exam questions test whether you can match controls to threats in context — not just recall definitions.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this PT0-002 question in full detail.
Tools and Code Analysis — This question tests Tools and Code Analysis — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: cut -d: -f1 /etc/passwd — Option A is correct because the `cut` command with `-d:` sets the field delimiter to colon (the separator in /etc/passwd) and `-f1` extracts the first field, which is the username. This is the most efficient and straightforward method for this specific task, as it directly isolates the username column without pattern matching or processing overhead.
What should I do if I get this PT0-002 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
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.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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