grep, egrep, fgrep – print lines matching a pattern
grep [OPTIONS] PATTERN [FILE…]
grep [OPTIONS] [-e PATTERN | -f FILE] [FILE…]
grep searches the named input FILEs (or standard input if no files are named, or if a single hyphen-minus (-) is given as file name) for lines containing a match to the given PATTERN. By default, grep prints the matching lines.
In addition, two variant programs egrep and fgrep are available. egrep is the same as grep -E. fgrep is the same…