grep
	Print lines matching a pattern
SYNOPSIS
	{[OPTIONS]} [PATTERN] [FILE/DIR...]
	{[OPTIONS]} [-e PATTERN | -f FILE] [FILE/DIR...]
USAGES
	{[OPTIONS]}
		-n
			Show line numbers
		-r, --recursive
			Read all files under each directory
			FILE must be a directory
			
	[PATTERN]
	[FILE]
		File or files to look through
EXAMPLES
	grep the *
		Look for 'the' in every file in present directory
	grep -nr patt .
		Look for 'patt' in every file in here, and show line numbers

