Estimate space used by directory.

du -sh dir

Go back to the previous folder

cd -

Mount a Windows FAT partition. If it is an NTFS partion, use ‘ntfs’ instead of ‘fat’. Make sure that the kernel support ntfs if you want to do that.

mount -t vfat /dev/hda5 /mnt/d

Modify timestamp of a file or directory

touch -t 0712250000 file #(YYMMDDhhmm)

Mount a windows network share in Linux using Samba

mount -t smbfs -o username=user,password=pass //WinClient/share /mnt/share

Cancel a planned shutdown of the system

shutdown -c

Linux Command to search the Harddisk for bad sectors

sudo badblocks -v /dev/sda

Shutdown the system after a specified time.

shutdown -h hours:minutes &

Erase a Rewritable Disk

cdrecord -v gracetime=2 dev=/dev/cdrom -eject blank=fast -force

Force umount when the device is busy

fuser -km /mnt/hda2