umount

 

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 UMOUNT(8)           Linux Programmer's Manual           UMOUNT(8)
 
 
 
NAME
        umount - unmount file systems
 
SYNOPSIS
        umount [-hV]
 
        umount -a [-nrv] [-t vfstype] [-O options]
        umount [-nrv] device | dir [...]
 
DESCRIPTION
        The  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 umount itself - it opens libc,  and  libc  in  its
        turn may open for example locale files.
 
        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 option type may be specified
               in a comma separated list.  Each option can be pre­
               fixed with no  to  specify  options  for  which  no
               action should be taken.
 
        -f     Force  unmount  (in case of an unreachable NFS sys­
               tem).  (Requires kernel 2.1.116 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)

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