learn linux terminal

I once heard an author say that when you are a child you use a computer by looking at the pictures. When you grow up, you learn to read and write.

Linux is a very powerful os but to unleash its full power , terminal use is a must.
I was just googling around and found a cool website t0 learn Linux terminal.
Here's the link - http://linuxcommand.org/lc3_learning_the_shell.php .Enjoy