cal() {
	local CURR_DAY_OF_MONTH CURR_MONTH_YEAR GRAD_MONTH_YEAR COLOR DECORATED_TEXT CAL_OPTS WHITESPACE EOL_STRIP
	local IFS='%'

	CURR_DAY_OF_MONTH="$(date +%e)"
	CURR_MONTH_YEAR="$(date +%B\ %Y)"
	GRAD_MONTH_YEAR="$(for COLOR in {17..21} 0 {21..17}; do [ "$COLOR" -eq 0 ] && DECORATED_TEXT="\e[7;49;33m ${CURR_MONTH_YEAR} \e[0m" || DECORATED_TEXT=" "; printf "\e[48;5;${COLOR}m${DECORATED_TEXT}\e[0m"; done)"

	case "$(uname)" in
	    Darwin)
		CAL_OPTS="-h"
		WHITESPACE=" "
		EOL_STRIP="s/(${WHITESPACE}{2})$//g;"
		;;
	    Linux)
		CAL_OPTS=""
		WHITESPACE="\s"
		EOL_STRIP=""
		;;
	esac

	[ -z "$1" ] \
		&& printf \
		"$(/usr/bin/cal ${CAL_OPTS} \
		| sed -r -e ${EOL_STRIP}'s/(^.* '${CURR_MONTH_YEAR}' .*$)/'${GRAD_MONTH_YEAR}'/g;s/^('${WHITESPACE}'*|'${WHITESPACE}'*[0-9].*)(('${CURR_DAY_OF_MONTH}')(('${WHITESPACE}'){1,2}[0-9]*.*$|$))/\\e[7;49;37m\1\\e[7;49;91m\3\\e[0m\\e[7;49;37m\4\\e[0m/g;')\n" \
		|| /usr/bin/cal $*

	unset IFS
}