Learn the Linux Command Line and Shell Scripting

ya good link but i'll never go for cli based os

Shell Scripting is not for all. Those people who are ready to toil hard & learn the
ways to master the Linux OS , can give it a try.

Hmm... i must say, iam addicted to shelll scripting and cammand line these days, I save so much time, by automating tasks, Shell scripting is a must if u want to do work efficiently and effectively.
It isn't a arcane dark art, its a philosophy of UNIX a way of life, we combine small small utilities into a big program, to do complex functions, thats why UNIX stuff is very efficient as the utilities are not 'Swiss army Knifes' they are efficient and simple and do their work effectively. But nonetheless powerfull.

There are more reference texts at www.tldp.org

I agree @Satish. Unix is more efficient than Windows. That's why Unix O.S is used for
launching a Space Shuttle. If you use Windows, you never know , since the Windows can
crash any time!!