UMOUNT(8)						     Linux Programmer's Manual							 UMOUNT(8)

NAME

       umount - unmount file systems

SYNOPSIS

       umount [-hV]

       umount -a [-dflnrv] [-t vfstype] [-O options]
       umount [-dflnrv] dir | device [...]

DESCRIPTION

       The umount command detaches the file system(s) mentioned from the file hierarchy.  A file system is specified by giving the directory where
       it has been mounted. Giving the special device on which the file system lives may also work, but is obsolete, mainly because it	will  fail
       in case this device was mounted on more than one directory.

       Note  that a file system cannot be unmounted when it is `busy' - for example, when there are open files on it, or when some process has its
       working directory there, or when a swap file on it is in use.  The offending process could even be umount itself - it opens libc, and  libc
       in its turn may open for example locale files.  A lazy unmount avoids this problem.

       Options for the umount command:

       -V     Print version and exit.

       -h     Print help message and exit.

       -v     Verbose mode.

       -n     Unmount without writing in /etc/mtab.

       -r     In case unmounting fails, try to remount read-only.

       -d     In case the unmounted device was a loop device, also free this loop device.

       -a     All  of  the  file  systems  described  in  /etc/mtab  are unmounted. (With umount version 2.7 and later: the proc filesystem is not
	      unmounted.)

       -t vfstype
	      Indicate that the actions should only be taken on file systems of the specified type.  More than one type  may  be  specified  in  a
	      comma  separated	list.	The  list of file system types can be prefixed with no to specify the file system types on which no action
	      should be taken.

       -O options
	      Indicate that the actions should only be taken on file systems with the specified options in /etc/fstab.	More than one option  type
	      may  be  specified  in a comma separated list.  Each option can be prefixed with no to specify options for which no action should be
	      taken.

       -f     Force unmount (in case of an unreachable NFS system).  (Requires kernel 2.1.116 or later.)

       -l     Lazy unmount. Detach the filesystem from the filesystem hierarchy now, and cleanup all references to the filesystem as soon as it is
	      not busy anymore.  (Requires kernel 2.4.11 or later.)

THE LOOP DEVICE

       The  umount  command  will free the loop device (if any) associated with the mount, in case it finds the option `loop=...' in /etc/mtab, or
       when the -d option was given.  Any pending loop devices can be freed using `losetup -d', see losetup(8).

FILES

       /etc/mtab table of mounted file systems

SEE ALSO

       umount(2), mount(8), losetup(8).

HISTORY

       A umount command appeared in Version 6 AT&T UNIX.

Linux 2.0							   26 July 1997 							 UMOUNT(8)