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 (or an
external unmount program) 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.
By default, the file system type is extracted from the kernel and used to choose
an external unmount program, whose name is formed by appending an underscore
and the type string to “umount”. This matches the form used by the
external mount programs used by
mount(8). If this program is
found on the path, it is used in preference to calling
unmount(2) directly. Note that
in the
NetBSD base system no such external unmount
programs exist; the facility is provided in the hopes that it will be useful
for third party file systems and/or for research.
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
actually 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 mechanically 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. This option also disables the use of any external
unmount program.
-
-
- -h
host
- Only filesystems mounted from the specified host will be
unmounted. This option is implies the -a option and,
unless otherwise specified with the -t option, will only
unmount NFS filesystems.
-
-
- -t
fstypelist
- Is used to indicate the actions should only be taken on
filesystems 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:
unmounts all filesystems of the type NFS and MFS, whereas the
umount command:
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 1
AT&T UNIX.