UMOUNT

NAME
SYNOPSIS
DESCRIPTION
THE LOOP DEVICE
FILES
SEE ALSO
HISTORY

NAME

umount − unmount file systems

SYNOPSIS

umount [−hV]

umount -a [−nrv] [−t vfstype]
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.

−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.

−f

Force unmount (in case of an unreachable NFS system). (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. 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.