Difficulty: Easy
Correct Answer: head
Explanation:
Introduction / Context:When inspecting configuration files or logs, you may only need the beginning of the file to verify headers or initial entries. UNIX/Linux provides head to quickly view the top lines without loading the entire file into a pager.
Given Data / Assumptions:
Concept / Approach:The head command reads from the start of a file and prints the first N lines. You can adjust N with -n N. It is fast and useful in pipelines. Other commands like more or less page through content interactively; grep filters by pattern, not position.
Step-by-Step Solution:
Preview first lines: head file.txtSpecify count: head -n 20 file.txtCombine with tail for middle slices: head -n 1000 file | tail -n 20Use in pipelines: gunzip -c huge.gz | headVerification / Alternative check:Compare with less file.txt and jump to the beginning; both show the same initial content. head is non-interactive and terminates immediately after printing the requested lines.
Why Other Options Are Wrong:grep: searches for patterns anywhere, not just the beginning. more: pager for interactive viewing. cat: dumps entire file; no line limit. None of the above: incorrect because head is correct.
Common Pitfalls:Confusing -n with byte options on some platforms (e.g., -c counts bytes). Forgetting that default is typically 10 lines, which may differ by implementation.
Final Answer:head
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