Download Videos from YouTube, TED, Dailymotion and other online video sites - Movgrab

Movgrab is a command line application to download video's from all those pesky sites that insist you use a big fat browser that runs flash in order to see their content. It's a command-line app written in straight C and does not require to install any other dependency packages.

Download and Install Movgrab:
Download the latest Movgrab source tar file - here
Open the terminal and type following command to compile and install Movgrab:

tar -zxvf movgrab-1.1.8.tgz
cd movgrab-1.1.8
./configure
make
sudo make install

Using Movgrab:
Generally you need to get the url of the webpage that the video would normally appear on if it were playing in your browser. Here are some examples of what URLs might look like:

Youtube: http://www.youtube.com/watch?v=9JqKN-nPjgA
Daily Motion: http://www.dailymotion.com/video/xp5j6w_big-cats-mirrors-funny_animals
TED: http://www.ted.com/talks/pranav_mistry_the_thrilling_potential_of_sixthsense_technology.html

Open the terminal and type following command to grab a video from youtube:

movgrab 'http://www.youtube.com/watch?v=9JqKN-nPjgA'

Note the use of quotes (') is a good idea, as many urls have characters like '&' in them that will confuse the shell if they are not in quotes.

There are many more options that you can use with movgrab command ...

'movgrab -?' or just 'movgrab' will print out a short usage instruction.

If you want to specify the file to save the move to, use '-o <filename>'.
Using '-o -' will pump the movie data out of stdout, so you can feed it to another program, like this:

movgrab -o -  http://www.youtube.com/watch?v=9JqKN-nPjgA | mplayer -

There are many more application through which you can download videos from various sites ...
Download or Stream Video/Audio files from Youtube - Gmediafinder
Graphical tool to Download and Convert YouTube Videos - CaC
Download videos from YouTube.com - youtube-dl
Download and Convert Videos from YouTube, Vimeo, Dailymotion and other online video sites - ClipGrab