[thirdparty/util-linux.git] / mount / umount.8

.\" Copyright (c) 1996 Andries Brouwer
.\" This page is somewhat derived from a page that was
.\" (c) 1980, 1989, 1991 The Regents of the University of California
.\" and had been heavily modified by Rik Faith and myself.
.\"
.\" This is free documentation; you can redistribute it and/or
.\" modify it under the terms of the GNU General Public License as
.\" published by the Free Software Foundation; either version 2 of
.\" the License, or (at your option) any later version.
.\"
.\" The GNU General Public License's references to "object code"
.\" and "executables" are to be interpreted as the output of any
.\" document formatting or typesetting system, including
.\" intermediate and printed output.
.\"
.\" This manual is distributed in the hope that it will be useful,
.\" but WITHOUT ANY WARRANTY; without even the implied warranty of
.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
.\" GNU General Public License for more details.
.\"
.\" You should have received a copy of the GNU General Public
.\" License along with this manual; if not, write to the Free
.\" Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139,
.\" USA.
.\"
.TH UMOUNT 8 "26 July 1997" "Linux 2.0" "Linux Programmer's Manual"
.SH NAME
umount \- unmount file systems
.SH SYNOPSIS
.BI "umount [\-hV]"
.LP
.BI "umount -a [\-nrv] [\-t " vfstype ]
.br
.BI "umount [\-nrv] " "device " | " dir " [...]
.SH DESCRIPTION
The
.B umount
command detaches the file system(s) mentioned from the file hierarchy.
A file system is specified either by giving the directory where it
has been mounted, or by giving the special device on which it lives.

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
.B umount
itself - it opens libc, and libc in its turn may open for example
locale files.

Options for the
.B umount
command:
.TP
.B \-V
Print version and exit.
.TP
.B \-h
Print help message and exit.
.TP
.B \-v
Verbose mode.
.TP
.B \-n
Unmount without writing in
.IR /etc/mtab .
.TP
.B \-r
In case unmounting fails, try to remount read-only.
.TP
.B \-a
All of the file systems described in
.I /etc/mtab
are unmounted. (With
.B umount
version 2.7 and later: the
.I proc
filesystem is not unmounted.)
.TP
.BI \-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
.B no
to specify the file system types on which no action should be taken.
.TP
.B \-f
Force unmount (in case of an unreachable NFS system).
(Requires kernel 2.1.116 or later.)

.SH "THE LOOP DEVICE"
The
.B umount
command will free the loop device (if any) associated
with the mount, in case it finds the option `loop=...' in
.IR /etc/mtab .
Any pending loop devices can be freed using `losetup -d', see
.BR losetup (8).


.SH FILES
.I /etc/mtab
table of mounted file systems

.SH "SEE ALSO"
.BR umount (2),
.BR mount (8),
.BR losetup (8).

.SH HISTORY
A
.B umount
command appeared in Version 6 AT&T UNIX.
Commit	Line	Data
fd6b7a7f KZ	1	.\" Copyright (c) 1996 Andries Brouwer
	2	.\" This page is somewhat derived from a page that was
	3	.\" (c) 1980, 1989, 1991 The Regents of the University of California
	4	.\" and had been heavily modified by Rik Faith and myself.
	5	.\"
	6	.\" This is free documentation; you can redistribute it and/or
	7	.\" modify it under the terms of the GNU General Public License as
	8	.\" published by the Free Software Foundation; either version 2 of
	9	.\" the License, or (at your option) any later version.
	10	.\"
	11	.\" The GNU General Public License's references to "object code"
	12	.\" and "executables" are to be interpreted as the output of any
	13	.\" document formatting or typesetting system, including
	14	.\" intermediate and printed output.
	15	.\"
	16	.\" This manual is distributed in the hope that it will be useful,
	17	.\" but WITHOUT ANY WARRANTY; without even the implied warranty of
	18	.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	19	.\" GNU General Public License for more details.
	20	.\"
	21	.\" You should have received a copy of the GNU General Public
	22	.\" License along with this manual; if not, write to the Free
	23	.\" Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139,
	24	.\" USA.
	25	.\"
	26	.TH UMOUNT 8 "26 July 1997" "Linux 2.0" "Linux Programmer's Manual"
	27	.SH NAME
	28	umount \- unmount file systems
	29	.SH SYNOPSIS
	30	.BI "umount [\-hV]"
	31	.LP
	32	.BI "umount -a [\-nrv] [\-t " vfstype ]
	33	.br
	34	.BI "umount [\-nrv] " "device " \| " dir " [...]
	35	.SH DESCRIPTION
	36	The
	37	.B umount
	38	command detaches the file system(s) mentioned from the file hierarchy.
	39	A file system is specified either by giving the directory where it
	40	has been mounted, or by giving the special device on which it lives.
	41
	42	Note that a file system cannot be unmounted when it is `busy' -
	43	for example, when there are open files on it, or when some process
	44	has its working directory there, or when a swap file on it is in use.
	45	The offending process could even be
	46	.B umount
	47	itself - it opens libc, and libc in its turn may open for example
	48	locale files.
	49
	50	Options for the
	51	.B umount
	52	command:
	53	.TP
	54	.B \-V
	55	Print version and exit.
	56	.TP
	57	.B \-h
	58	Print help message and exit.
	59	.TP
	60	.B \-v
	61	Verbose mode.
	62	.TP
	63	.B \-n
	64	Unmount without writing in
65	.IR /etc/mtab .
66	.TP
67	.B \-r
68	In case unmounting fails, try to remount read-only.
69	.TP
70	.B \-a
71	All of the file systems described in
72	.I /etc/mtab
73	are unmounted. (With
74	.B umount
75	version 2.7 and later: the
76	.I proc
77	filesystem is not unmounted.)
78	.TP
79	.BI \-t " vfstype"
80	Indicate that the actions should only be taken on file systems of the
81	specified type. More than one type may be specified in a comma separated
82	list. The list of file system types can be prefixed with
83	.B no
84	to specify the file system types on which no action should be taken.
7eda085c KZ	85	.TP
	86	.B \-f
	87	Force unmount (in case of an unreachable NFS system).
	88	(Requires kernel 2.1.116 or later.)
fd6b7a7f KZ	89
	90	.SH "THE LOOP DEVICE"
	91	The
	92	.B umount
	93	command will free the loop device (if any) associated
	94	with the mount, in case it finds the option `loop=...' in
	95	.IR /etc/mtab .
	96	Any pending loop devices can be freed using `losetup -d', see
	97	.BR losetup (8).
	98
	99
	100	.SH FILES
	101	.I /etc/mtab
	102	table of mounted file systems
	103
	104	.SH "SEE ALSO"
	105	.BR umount (2),
	106	.BR mount (8),
	107	.BR losetup (8).
	108
	109	.SH HISTORY
	110	A
	111	.B umount
	112	command appeared in Version 6 AT&T UNIX.