Linux: youtube-dl

Debian instalation:

       sudo curl https://yt-dl.org/downloads/2014.04.04.7/youtube-dl -o /usr/local/bin/youtube-dl
       sudo chmod a+x /usr/local/bin/youtube-dl

Ussage:

       youtube-dl <URL>
       youtube-dl --max-quality=mp4 http://www.youtube.com/NOMBREdeVIDEO
       youtube-dl --extract-audio --audio-format mp3 https://www.youtube.com/watch?v=6NsGQ2liIkk