#!/bin/sh

while true
do 
	volume="$(mpc volume | awk '{print $2}' | cut -f1 -d'%')"
	choice="$(printf "plus\nmin\n" |
		commander -d -c -p "$volume" |
		sed 's/plus/+/;s/min/-/')"
	[ "$choice" ] || break
	nb="$(commander -c -p "$volume$choice" -i)"
	[ "$nb" ] || break
	mpc volume "$choice$nb"
done