Parse logs with grep, sed, and awk on Linux

1. Goal

Extract useful information from logs with simple pipelines you can reuse in daily admin work.

2. Files and components involved

grep
sed
awk
/var/log/messages
/var/log/secure

3. Operational flow

grep -i error /var/log/messages
awk on /var/log/secure
sed -n on maillog
save pipeline utili in script

4. Operational verification

grep -c pattern filelog
awk report
sort
uniq -c
head

5. Practical notes

Before using a script in production, always test the full flow with controlled input, logs, and exit codes.

Quick checklist

[ ] Backup or copy of the existing configuration completed
[ ] Files and commands updated as expected
[ ] Local test completed successfully
[ ] Logs or final output verified
[ ] Rollback procedure documented

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