#!/bin/bash

count=0;
( for file in "$@"; do
    ffmpeg -nostdin -y -i "$file" "$file.mp3" 
    count=$(echo "($count + 1)" | bc)

    percent=$(echo " scale=2; ( 100 * ($count/$#))" | bc )
    echo "$percent"
done ) |  zenity --progress --percentage=0 --auto-close --text="Converting files"