hl

# hl - highlight
# Takes a maximum of 28 "egrep" regex-es as parameters, and highlights them in the text coming from stdin, using various colors.
# Patterns to the right are "stronger", but keep in mind that the input might already contain ANSI control characters.
function hl ()
{
	local cmd
	local i
	local color
	i=1
	cmd="cat"
	while [[ $# -gt 0 ]]; do
		if [[ "${1}" != "." ]]; then # Use "." to skip a color you don't like
			if [[ $i -lt 8 ]]; then
				color="7\;$(( 30 + ${i} ))" # background
			elif [[ $i -lt 14 ]]; then
				color="$(( 30 - 7 + ${i} ))" # foreground color
			elif [[ $i -lt 21 ]]; then
				color="7\;2\;$(( 30 - 13 + ${i} ))" # background, faint
			elif [[ $i -lt 28 ]]; then
				color="4\;$(( 30 - 20 + ${i} ))" # underlined, foreground
			fi
			cmd="$cmd | GREP_COLOR="${color}" egrep --color=always --line-buffered '${1}|$'"
		fi
		shift
		i=$(( $i+1 ))
	done
	$SHELL -c "$cmd"
}