grep — searching text

Cheat sheet

• grep -i word file case-insensitive
• grep -rn word dir/ recursive + line numbers
• grep -v word file lines without the word
• grep -C2 word file ±2 lines of context
• grep -rn --include='*.conf' word /etc
• grep -oP 'regex' file match only, Perl regex
• cmd | grep -F "literal" a literal string

Options

Flag	Meaning
-i	case-insensitive
-r / -R	recursive through directories (R also follows symlinks)
-n	show line numbers
-v	invert (lines WITHOUT the pattern)
-c	count matches
-l / -L	only filenames with a match / without one
-w / -x	a whole word / a whole line
-E / -F / -P	extended regex / a fixed string / Perl regex
-A N/-B N/-C N	N lines after / before / around
-o	only the matched part
--include/--exclude	filter filenames with -r