Script that makes use of youtube-dl and ffmpeg to cleanly extract mp3 out of Youtube videos.

youtube-dl-mp3

# Get/download youtube-dl from http://rg3.github.com/youtube-dl/
# Make it executable (chmod +x <path-to-youtube-dl>/youtube-dl)
# Copy it to /usr/bin to use it like a command (sudo cp <path-to-youtube-dl>/youtube-dl /usr/bin)
# Open your favourite editor and copy this script and save by any name you like (I use youtube-dl-mp3).
# Make it executable (chmod +x <path-to-youtube-dl-mp3>/youtube-dl-mp3)
# Copy it to /usr/bin to use it like a command (sudo cp <path-to-youtube-dl-mp3>/youtube-dl-mp3 /usr/bin)
# Done! :)
# Usage: youtube-dl-mp3 "http://www.youtube.com/watch?v=YnA6ExlxNJU&feature=fvst"

if [ -w "." ]
then
  echo ""
else
  echo "You don't have write permissions in this directory."
  exit
fi

title=`youtube-dl --get-title "$1"`
start=`echo $title| awk '{ print $1 }' `

youtube-dl -o "%(stitle)s.%(ext)s" "$1"

file=`ls *$start*.mp4`
file_name=`echo $file| cut -d '.' -f1`
file_ext=`echo $file| cut -d '.' -f2`

ffmpeg -i "$file" -ab 160k -ac 2 -ar 44100 -vn "$file_name.mp3"
rm -f "$file"