Download youtube in Ubuntu

Install youtube-dl in Ubuntu

linux terminal:~$ 

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

To download a video, simply use the following command:

linux terminal:~$ 
youtube-dl http://VIDEO_URL 

where "VIDEO_URL" is the url of the video you want to download. 

To see all the available options, type the following commands in a terminal: "man youtube-dl" or "youtube-dl -h".