sudo apt-get install pip
pip install youtube-dl

sudo add-apt-repository ppa:nilarimogard/webupd8 -y
sudo apt-get update
sudo apt-get install youtube-dl

youtube-dl ytuser:<USER>

youtube-dl <PLAYLIST URL>

youtube-dl -x --audio-format mp3 --audio-quality 320K <VIDEO_URL>

-f, --format FORMAT
video format code. The special name "best" will pick the best quality.