Run fsck on a filesystem to repair it..

fsck -y -o b=32 /filesystem

This will repair the corrupted file system to its best and restore the data in /filesystem/lost+found directory. Data in this directory will have "#inode name" nomenclature. From there the data can be copied back to the filesystem. Ofcourse the techie who is repairing the FS must have prior knowledge about the directory structure in filesystem otherwise he would not be able to decide where to copy which file from lost+found directory. 

Note: This is system administrator's work, so please do not run mount/umount/fsck sort of commands with minimal knowledge. The fsck command can have other parameters as well. So depending on the need of the work, one can decide the exact fsck command. Above fsck command is most generic one i came across and applied while **working on real time issues**. Also please keep in mind that the filesystem has to be unmounted first (umount /filesystem) then run fsck and then mount (mount /filesystem /mountpoint) the filesystem back if properly repaired. Then only you will be able to see the files for restore in /lost+found directory.

Mount ISO image in Linux

Getting a lot of emails regarding mounting ISOs in linux. Please use the following steps in order to mount the image to FS.

Procedure to mount ISO images in Linux.

1) Login as a root user:
$ su -

2) Create a mount point:
# mkdir -p /mnt/disk

3) Mount iso file called mountthisdisk.iso:
# mount -o loop mountthisdisk.iso /mnt/disk

4) Verify it:
# cd /mnt/disk
# ls -l

In case you have not noticed "loop" in the mount command, let me tell you that A loop device is a pseudo-device that makes a file accessible as a block device. Loop devices are often used for CD ISO images and floppy disc images. Mounting a file containing a filesystem via such a loop mount makes the files within that filesystem accessible. They appear in the mount point directory using above commands.