You run grep alice /var/log/cron tail -n 3 but get an error: 'grep: invalid option -- n'. What is the mistake?

medium📝 Troubleshoot Q7 of 15

Linux CLI - Cron and Scheduling

You run grep alice /var/log/cron tail -n 3 but get an error: 'grep: invalid option -- n'. What is the mistake?

AThe command should be <code>tail -n 3 grep alice /var/log/cron</code>

BThe tail command should be used after grep, not as an option to grep

CThe file /var/log/cron does not exist

Dgrep does not support piping

Step-by-Step Solution

Solution:

Step 1: Analyze error message
grep reports invalid option -n, meaning tail's option was incorrectly passed to grep.
Step 2: Check command syntax
Correct syntax is to pipe grep output to tail: grep alice /var/log/cron | tail -n 3. If tail is inside grep, it causes error.
Final Answer:
The tail command should be used after grep, not as an option to grep -> Option B
Quick Check:
Pipe commands correctly: grep ... | tail ... [OK]

Quick Trick: Use pipe '|' to chain commands, not options inside commands [OK]

Common Mistakes:

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