`grep` Search text for lines that match a pattern

Reads files or piped input and prints the lines that match a pattern. Use it to find an error in a log, a word in a set of files, or to filter the output of another command.

Synopsis

grep [OPTION]... PATTERN [FILE]...
command | grep [OPTION]... PATTERN

Common options

Option or form	What it does
`-i`	Ignore case, so error matches Error and ERROR
`-v`	Invert the match: print the lines that do not match
`-n`	Put the line number in front of each matching line
`-r, -R`	Search every file under the given folders. On macOS and BSD, give a folder such as . explicitly
`-c`	Print only the number of matching lines, not the lines themselves
`-E`	Use extended regular expressions, so \| (or), + and ? work without backslashes
`-l`	Print only the names of files that contain a match
`-w`	Match whole words only, so cat does not match category

Examples

Find lines containing a word

grep error notes.txt

beta error
error: disk full

Ignore case and show line numbers

grep -in beta notes.txt

2:beta error
4:Beta again

Count matching lines

grep -c ERROR app.log

Show every line except the matches

grep -v error notes.txt

alpha
gamma
Beta again
delta

List the files that contain a word

grep -rl ERROR .

./app.log

Match one of several patterns

grep -E 'ERROR|WARN' app.log

2026-01-01 ERROR failed to open
2026-01-02 WARN slow
2026-01-02 ERROR timeout

Notes

Exit status: 0 if at least one line matched, 1 if nothing matched, 2 if there was an error such as a missing file. Scripts use this, for example: grep -q fig words.txt && echo found. The -q flag prints nothing and only sets the status.
Put the pattern in quotes when it has spaces, *, | or $. Otherwise the shell changes it before grep sees it.
Plain grep uses basic regular expressions. Characters such as + and | have no special meaning unless you add -E. On macOS, the backslash form \+ is not reliable, so use -E instead.
To search for text exactly as typed, with no pattern characters, use -F. Use -o to print only the matched part, and -A, -B or -C with a number to show lines around each match.
With more than one file, grep puts the file name in front of each line. Use -h to hide it, or -H to show it for a single file.

grep Search text for lines that match a pattern

Synopsis

Common options

Examples

Notes

See also

`grep` Search text for lines that match a pattern