1.\" Copyright (c) 1980, 1989, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 4. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" @(#)umount.8 8.2 (Berkeley) 5/8/95 29.\" $FreeBSD$ 30.\" 31.Dd May 31, 2011 32.Dt UMOUNT 8 33.Os 34.Sh NAME 35.Nm umount 36.Nd unmount file systems 37.Sh SYNOPSIS 38.Nm 39.Op Fl fv 40.Ar special ... | node ... | fsid ... 41.Nm 42.Fl a | A 43.Op Fl F Ar fstab 44.Op Fl fv 45.Op Fl h Ar host 46.Op Fl t Ar type 47.Sh DESCRIPTION 48The 49.Nm 50utility calls the 51.Xr unmount 2 52system call to remove a file system from the file system tree. 53The file system can be specified by its 54.Ar special 55device or remote node (rhost:path), the path to the mount point 56.Ar node 57or by the file system ID 58.Ar fsid 59as reported by 60.Dq mount -v 61when run by root. 62.Pp 63The options are as follows: 64.Bl -tag -width indent 65.It Fl a 66All the file systems described in 67.Xr fstab 5 68are unmounted. 69.It Fl A 70All the currently mounted file systems except 71the root are unmounted. 72.It Fl F Ar fstab 73Specify the 74.Pa fstab 75file to use. 76.It Fl f 77The file system is forcibly unmounted. 78Active special devices continue to work, 79but all other files return errors if further accesses are attempted. 80The root file system cannot be forcibly unmounted. 81For NFS, a forced dismount can take up to 1 minute or more to 82complete against an unresponsive server and may throw away 83data not yet written to the server for this case. 84.It Fl h Ar host 85Only file systems mounted from the specified host will be 86unmounted. 87This option implies the 88.Fl A 89option and, unless otherwise specified with the 90.Fl t 91option, will only unmount 92.Tn NFS 93file systems. 94.It Fl t Ar type 95Is used to indicate the actions should only be taken on 96file systems of the specified type. 97More than one type may be specified in a comma separated list. 98The list of file system types can be prefixed with 99.Dq no 100to specify the file system types for which action should 101.Em not 102be taken. 103For example, the 104.Nm 105command: 106.Bd -literal -offset indent 107umount -a -t nfs,nullfs 108.Ed 109.Pp 110unmounts all file systems of the type 111.Tn NFS 112and 113.Tn NULLFS 114that are listed in the 115.Xr fstab 5 116file. 117.It Fl v 118Verbose, additional information is printed out as each file system 119is unmounted. 120.El 121.Sh ENVIRONMENT 122.Bl -tag -width ".Ev PATH_FSTAB" 123.It Ev PATH_FSTAB 124If the environment variable 125.Ev PATH_FSTAB 126is set, all operations are performed against the specified file. 127.Ev PATH_FSTAB 128will not be honored if the process environment or memory address space is 129considered 130.Dq tainted . 131(See 132.Xr issetugid 2 133for more information.) 134.El 135.Sh FILES 136.Bl -tag -width /etc/fstab -compact 137.It Pa /etc/fstab 138file system table 139.El 140.Sh SEE ALSO 141.Xr unmount 2 , 142.Xr fstab 5 , 143.Xr mount 8 144.Sh HISTORY 145A 146.Nm 147utility appeared in 148.At v6 . 149