Repair corrupted Ubuntu file system error (Solved)

One day suddenly you found that your Ubuntu machine is not opening. It says

GRUB loading.
error:unknown filesystem
grub rescue>

So, you should understand that your home or filesystem (root) has crashed. All thing has gone aka vanished. Don't worry friend. Here is a method to solve your problem. This command can repair a bad file system and can help you to backup valuable data.

Run with a live Ubuntu CD. When desktop appear open terminal and type:

sudo fsck.ext4 -f /dev/sda?

Replace '?' with your corrupted/ damaged partition number. It might be sda1 or sda2 or else. If your file system is ext3 then replace 'ext4' with 'ext3'. So the command may look like

sudo fsck.ext4 -f /dev/sda1

You may need to type password and press 'Y' if it require.

Sorry, to say that I have managed to repair/ restore my friends file system with this command. But my own crashed file system (Hard disk partition) did not obey this command. So do it at your own risk.