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LPIC-1 GNU and Unix Commands Practice Question

A systems administrator needs to find all files in /var/log that were modified in the last 24 hours and contain the word 'error'. Which command accomplishes this?

⚠ Common exam trap

Candidates often confuse `grep` options with `find` options (like `-mtime`) or forget that `grep` alone cannot filter by file modification time, leading them to choose Option A or C without recognizing the missing `-l` flag or syntax errors.

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

✓

find /var/log -mtime 0 -exec grep -l 'error' {} \;

It uses `find` with `-mtime 0` to locate files modified within the last 24 hours, then pipes each found file to `grep -l` to print only filenames containing 'error'. The `-exec` option runs `grep` on each file individually, and `-l` ensures only matching filenames are output, not the matching lines.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

✗
grep -r 'error' /var/log -mtime 0
Why it's wrong here
The -mtime option is not valid for grep.
✓
find /var/log -mtime 0 -exec grep -l 'error' {} \;
Why this is correct
Correctly uses find to filter by modification time and grep to search content.
✗
find /var/log -mmin 1440 -exec grep 'error' {}
Why it's wrong here
Missing -l flag and broken syntax; also -mmin is not standard for 24 hours.
✗
ls -l /var/log | grep error
Why it's wrong here
ls does not search file contents.

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LPIC-1 GNU and Unix Commands Practice Question

Why each option matters

Option-by-option breakdown

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