grep

The grep command in Linux is a powerful tool for searching text patterns within files. It allows users to specify a pattern, such as a word or phrase, and efficiently finds all matching lines.

Examples:

grep security messages.log

Searches for the word “security” in ‘messages.log’.

grep -i security messages.log

Ignores case, finding both “Security” and “security”.

grep -n security messages.log

Outputs matches preceded by the line number.

grep -n 5 security messages.log

Stops after finding five matches.

grep security file1.log file2.log

Searches both files for “security”.

These examples showcase the versatility of grep, from basic searches to more complex operations, making it an essential tool for text manipulation and analysis.