Download music from YouTube and convert it to an MP3 file.
Install via apt:
$ sudo apt install youtube-dl
Install via pip3
$ sudo pip3 install -U youtube-dl
$ sudo apt install ffmpeg lame
$ curl -O https://raw.githubusercontent.com/jgeewax/youtube-song/master/youtube-song
$ chmod a+x youtube-song
$ # Optional
$ sudo mv youtube-song /usr/local/bin/
$ youtube-song "https://www.youtube.com/watch?v=dQw4w9WgXcQ" "Avicii - Levels.mp3"