Linux CLI - Cron and Scheduling
You want to monitor cron logs for failures only. Which command combination will show lines containing 'CRON' and 'FAILED' in real time?
You want to monitor cron logs for failures only. Which command combination will show lines containing 'CRON' and 'FAILED' in real time?
hard📝 Workflow Q8 of 15
Step-by-Step Solution
Solution:
Step 1: Understand filtering multiple patterns
To show lines containing both 'CRON' and 'FAILED', pipe grep twice: first for 'CRON', then for 'FAILED'.Step 2: Analyze options
grep 'FAILED' /var/log/cron | tail -f is invalid because tail -f cannot follow piped input. tail -f /var/log/cron | grep 'FAILED CRON' searches for combined string 'FAILED CRON' which is unlikely. tail -f /var/log/cron | grep -e 'CRON' -e 'FAILED' shows lines with either 'CRON' or 'FAILED', not both.Final Answer:
tail -f /var/log/cron | grep 'CRON' | grep 'FAILED' -> Option DQuick Check:
Chain grep to filter multiple patterns [OK]
Quick Trick: Use multiple grep pipes to filter multiple keywords [OK]
Common Mistakes:
- Using grep -e with OR instead of AND logic
- Trying to tail -f after grep
- Searching for combined string instead of separate keywords
Master "Cron and Scheduling" in Linux CLI
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