or example, if a filesystem that is physically located on the second partition of the first HDD (which is designated by dev/hda2) is mounted in a directory called /dir2, it can be unmounted with either of the following:

umount /dir2


umount /dev/hda2 /dir2

Interestingly, when the physical device is included, a confirmation message is automatically supplied.

There are several options that can be tried in the event that umount refuses to unmount a filesystem for no immediately apparent reason. Perhaps the most useful is the -l (i.e., lazy) option, which immediately detaches the filesystem from the main filesystem and then cleans up all references to the unmounted filesystem as soon as it is no longer busy. This capability requires Linux kernel 2.4.11 or later.