countdown() {
	if [ -z "$1" ]; then
		printf "
countdown: Count down while printing progress on the terminal

Usage: countdown <seconds>
"
	fi
	local secs="$1"
	while [ "$secs" -gt 0 ]; do
		echo -ne "$secs\033[0K\r"
		sleep 1
		: $((secs--))
	done
}