print lines matching a pattern |
-n, --line-number Prefix each line of output with the 1-based line number within its input file. (-n is specified by POSIX.) |
-R, -r, --recursive Read all files under each directory, recursively; this is equivalent to the -d recurse option. |
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. |