linux convert youtube to mp3

#aptitude install youtube-dl ffmpeg libmp3lame

#!/bin/bash
x=/tmp/youtube-dl-$RANDOM-$RANDOM.flv
youtube-dl --output=$x --format=18 "http://www.youtube.com/watch?v=$1"
echo "convert flv to mp3"
ffmpeg -i $x -acodec libmp3lame -ac 2 -ab 128k -vn -y "/home/paragasu/mp3/youtube/$2"
rm $x
echo "done"

$youtube linkname fileoutput.mp3