Everyone downloads videos and audio from YouTube. There are countless plugins for it. Some work. Some don’t. Some just redirect you to their website. Some just stalk your browsing history.

youtube-dl is the solution [1]

$ sudo apt-get install youtube-dl

Downloading Video
$ youtube-dl {videourl}

Downloading only the MP3, [2]
$ youtube-dl --extract-audio --audio-format mp3 {videourl}

Isn’t it awesome?