Simple timer (shell scripts, uses notify-send)

simple-timer.sh

#!/usr/bin/env bash

function help() {
	echo "Please, run this script with one argument."
	echo "Examples:"
	echo "1) $0 1h"
	echo "2) $0 30m"
	echo "3) $0 125s"
	echo "4) $0 1h <your message>"
	echo "5) $0 30m <your message>"
	echo "6) $0 125s <your message>"
}

if [[ $# -gt 0 ]]
then
	if [[ $1 =~ ^[1-9]*[0-9]*[h|m|s]$ ]]
	then
		sleep $1 &&
		notify-send --urgency normal \
		 --expire-time=10000 \
		 -i /usr/share/icons/hicolor/48x48/apps/unity-datetime-panel.png \
		 "Timer" "$2"
	else
		help
	fi
else
	help
fi