Text processing

Unix text tools are built for streaming. grep filters, awk transforms, and sed edits.

When to use each

• grep: Find matching lines quickly.
• awk: Parse fields, calculate metrics, format output.
• sed: Edit streams with substitutions or line operations.

Example pipeline

journalctl -u nginx | grep " 5" | awk '{print $1, $2, $3, $9}' | sort | uniq -c