grep

Usage: grep [OPTIONS]... PATTERN [FILE]...

Search for PATTERN in each FILE or stdin.

Options:

			-h	Suppress the prefixing filename on output
			-i	Ignore case distinctions
			-n	Print line number with output lines
			-q	Be quiet. Returns 0 if result was found, 1 otherwise
			-v	Select non-matching lines
		

This version of grep matches full regular expressions.

Example:

			$ grep root /etc/passwd
			root:x:0:0:root:/root:/bin/bash
			$ grep ^[rR]oo. /etc/passwd
			root:x:0:0:root:/root:/bin/bash