How to format / partition?
 

I want to learn how I can format or run fsck command on / partition.

Since the / partition is always mounted when system is on, its dangerous to run fsck on a mounted partition.

Can somebody pls help me out with all the possible ways in detail?

you need to boot another os, for example a live cd.

You can use a live CD. BTW, why?

@Enindu: Just for learning purpose, Curiosity!!

BTW, I am a newbie. Could you pls elaborate on live cd. What is it and how it works? and all the steps.

download your preferred one, copy it onto a pendrive or CD and boot from that device.
Your original root will not be mounted, therefore you will be able to run fsck on that (or format, but format will destroy the old filesystem)

http://www.livecdlist.com/

Live CD is a just another operating system based CD image. Normally, it's run on RAM disk. That means, it can work without hard disk. All Linux distributions are live CDs. So, you can use any Linux distribution as a live CD. Not a big deal. BTW, what did you mean by 'all steps'? 'fsck' manual or something? Open terminal and type 'man fsck' for manual.