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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       lives may also work, but	is obsolete, mainly because it	will  fail  in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 ex-
       ample, 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 of-
       fending 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 pre-
	      fixed with no to specify the file	system types on	which  no  ac-
	      tion 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  hierar-
	      chy 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)

NAME | SYNOPSIS | DESCRIPTION | THE LOOP DEVICE | FILES | SEE ALSO | HISTORY

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