#!/bin/sh
volume=0
while true
do 
	volume="$(dmenu -p "$(mpc volume)" < /dev/null)"
	test -z "$volume" && break
	mpc volume "$(echo -e "plus\nmin" | 
		dmenu -g 2 -l 1 | 
		sed 's/plus/+/;s/min/-/')$volume"
done