youtube-dl is a Python program which lets you download videos from sites like YouTube, vimeo and many more onto your computer. It will even download entire YouTube playlists, works across all platforms and is easy to install and use.
Follow the simple instructions on the youtube-dl documentation page (downloads are at the youtube-dl download page). Don’t forget you’ll need Python 2.6, 2.7 or 3.3+ already installed on your computer.
For my Ubuntu 12.04 machine, this meant opening the terminal and running:
$sudo mkdir /usr/local/bin
$sudo wget http://youtube-dl.org/downloads/2013.01.13/youtube-dl -O /usr/local/bin/youtube-dl
$sudo chmod a+x /usr/local/bin/youtube-dl
In the terminal,
cd to the directory where you want to save your videos and run
The URL can be for an individual YouTube video, playlist or even search. Plenty of other sites are also supported.
Warning: Be careful if you have social media accounts linked to YouTube and you decide to create a public playlist for downloading with youtube-dl. Speaking from bitter experience, your followers/friends may end up being bombarded with YouTube posts if your privacy settings aren’t correctly configured!