On Unix/Linux, which command counts the total number of lines, words, and bytes/characters in a file in one invocation?
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Awc
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Bcountw
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Cwcount
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Dcount p
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ENone of the above
Answer
Correct Answer: wc
Explanation
Introduction / Context:When auditing logs, measuring dataset sizes, or validating script output, a compact summary of lines, words, and bytes is helpful. Unix/Linux provides a standard utility that computes these metrics efficiently for one or many files and can be combined with pipelines for flexible analysis.
Given Data / Assumptions:
- You have one or more text or binary files.
- You need counts for lines, words, and bytes/characters.
- POSIX shell tools are available.
Concept / Approach:The 'wc' command (word count) reports three values by default: line count, word count, and byte count (often interpreted as characters for single-byte encodings). Options '-l', '-w', and '-c' restrict output to a specific metric. With multiple files, 'wc' prints per-file statistics and an aggregate total line at the end.
Step-by-Step Solution:
Basic use: wc filenameCount only lines: wc -l filenameCount only words: wc -w filenameCount only bytes: wc -c filenameVerification / Alternative check:Cross-verify bytes with 'stat -c %s filename' (GNU) and lines with 'nl' or 'awk 'END{print NR}' filename'. The results should match for regular files.
Why Other Options Are Wrong:
- countw / wcount / count p: Not standard Unix commands.
- None of the above: Incorrect because 'wc' is correct.
Common Pitfalls:Confusing bytes with characters in multibyte encodings, and forgetting that 'wc' on stdin (for example, 'wc < file') omits the filename in the output format.
Final Answer:wc