umount(8) - NetBSD Manual Pages

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UMOUNT(8)               NetBSD System Manager's Manual               UMOUNT(8)


NAME

     umount -- unmount filesystems


SYNOPSIS

     umount [-fvFR] [-t fstypelist] special | node
     umount -a [-fvF] [-h host] [-t fstypelist]


DESCRIPTION

     The umount command calls the unmount(2) system call to remove a special
     device or the remote node (rhost:path) from the filesystem tree at the
     point node.  If either special or node are not provided, the appropriate
     information is taken from the fstab(5) file.

     The options are as follows:

     -a      All the currently mounted filesystems except the root are
             unmounted.

     -f      The filesystem is forcibly unmounted.  Active special devices
             continue to work, but all other files return errors if further
             accesses are attempted.  The root filesystem cannot be forcibly
             unmounted.

     -F      Fake the unmount; perform all other processing but do not actu-
             ally attempt the unmount.  (This is most useful in conjunction
             with -v, to see what umount would attempt to do).

     -R      Take the special | node argument as a path to be passed directly
             to unmount(2), bypassing all attempts to be smart about mechani-
             cally determining the correct path from the argument.  This
             option is incompatible with any option that potentially unmounts
             more than one filesystem, such as -a, but it can be used with -f
             and/or -v.  This is the only way to unmount something that does
             not appear as a directory (such as a nullfs mount of a plain
             file); there are probably other cases where it is necessary.

     -h host
             Only filesystems mounted from the specified host will be
             unmounted.  This option is implies the -a option and, unless oth-
             erwise specified with the -t option, will only unmount NFS
             filesystems.

     -t fstypelist
             Is used to indicate the actions should only be taken on filesys-
             tems of the specified type.  More than one type may be specified
             in a comma separated list.  The list of filesystem types can be
             prefixed with ``no'' to specify the filesystem types for which
             action should not be taken.  For example, the umount command:

                   umount -a -t nfs,mfs

             unmounts all filesystems of the type NFS and MFS, whereas the
             umount command:

                   umount -a -t nonfs,mfs

             unmounts all file systems except those of type NFS and MFS.

     -v      Verbose, additional information is printed out as each filesystem
             is unmounted.


FILES

     /etc/fstab  filesystem table


SEE ALSO

     unmount(2), fstab(5), mount(8)


HISTORY

     A umount command appeared in Version 6 AT&T UNIX.

NetBSD 6.1.3                     May 17, 2009                     NetBSD 6.1.3