2.3. Unmounting a File System
			To detach a previously mounted file system, use either of the following variants of the 
umount command:
		umount directory umount device
umount directory
umount device
			Note that unless you are logged in as 
root, you must have permissions to unmount the file system (see Section 2.2.2, “Specifying the Mount Options”). See Example 2.9, “Unmounting a CD” for an example usage.
		Important
				When a file system is in use (for example, when a process is reading a file on this file system), running the 
umount command will fail with an error. To determine which processes are accessing the file system, use the fuser command in the following form:
			fuser -m directory
fuser -m directory
				For example, to list the processes that are accessing a file system mounted to the 
/media/cdrom/ directory, type:
			fuser -m /media/cdrom
~]$ fuser -m /media/cdrom
/media/cdrom:         1793  2013  2022  2435 10532c 10672cExample 2.9. Unmounting a CD
				To unmount a CD that was previously mounted to the 
/media/cdrom/ directory, type the following at a shell prompt:
			umount /media/cdrom
~]$ umount /media/cdrom