UTube Ripper offers a graphical interface for downloading and converting the YouTube videos in Linux. But in many scenarios you also need to download some YouTube videos from command line. Just like if you are working on a remote sever and you need to download some video there, and you don’t have a graphical end available on the remote server, then what will you do? Try YouTube-Dl. It downloads YouTube videos from the command line and works on Linux, Unix, and Mac OS.
Lets see how we can install and use it in Ubuntu, first of all open the terminal and run the following command to install it.
sudo apt-get install youtube-dl
Once the installation is completed, you are ready to download YouTube videos. Now use the following general syntax of the command to download YouTube vide.
youtube-dl –o filename.flv URL
where filename.flv should be the name with which you wish to save the downloaded  video and URL is the address of the YouTube video. For e.g, see code below,
youtube-dl –o filename.flv http://www.youtube.com/watch?v=Ut3HAdCGHxs
The following screenshot illustrates the download process of the video in Ubuntu terminal:

Enjoy!