mount/umount.8

   1 .\" Copyright (c) 1996 Andries Brouwer
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  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 \-d
  71 In case the unmounted device was a loop device, also
  72 free this loop device.
  73 .TP
  74 .B \-a
  75 All of the file systems described in
  76 .I /etc/mtab
  77 are unmounted. (With
  78 .B umount
  79 version 2.7 and later: the
  80 .I proc
  81 filesystem is not unmounted.)
  82 .TP
  83 .BI \-t " vfstype"
  84 Indicate that the actions should only be taken on file systems of the
  85 specified type.  More than one type may be specified in a comma separated
  86 list.  The list of file system types can be prefixed with
  87 .B no
  88 to specify the file system types on which no action should be taken.
  89 .TP
  90 .B \-f
  91 Force unmount (in case of an unreachable NFS system).
  92 (Requires kernel 2.1.116 or later.)
  93
  94 .SH "THE LOOP DEVICE"
  95 The
  96 .B umount
  97 command will free the loop device (if any) associated
  98 with the mount, in case it finds the option `loop=...' in
  99 .IR /etc/mtab ,
 100 or when the \-d option was given.
 101 Any pending loop devices can be freed using `losetup -d', see
 102 .BR losetup (8).
 103
 104
 105 .SH FILES
 106 .I /etc/mtab
 107 table of mounted file systems
 108
 109 .SH "SEE ALSO"
 110 .BR umount (2),
 111 .BR mount (8),
 112 .BR losetup (8).
 113
 114 .SH HISTORY
 115 A
 116 .B umount
 117 command appeared in Version 6 AT&T UNIX.