umount(8) — Linux manual page


UMOUNT(8)                   System Administration                  UMOUNT(8)

NAME         top

       umount - unmount filesystems

SYNOPSIS         top

       umount -a [-dflnrv] [-t fstype] [-O option...]

       umount [-dflnrv] {directory|device}...

       umount -h|-V

DESCRIPTION         top

       The umount command detaches the mentioned filesystem(s) from the file
       hierarchy.  A filesystem is specified by giving the directory where
       it has been mounted.  Giving the special device on which the
       filesystem lives may also work, but is obsolete, mainly because it
       will fail in case this device was mounted on more than one directory.

       Note that a filesystem 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.  A lazy
       unmount avoids this problem, but it may introduce other issues. See
       --lazy description below.

OPTIONS         top

       -a, --all
              All of the filesystems described in /proc/self/mountinfo (or
              in deprecated /etc/mtab) are unmounted, except the proc,
              devfs, devpts, sysfs, rpc_pipefs and nfsd filesystems. This
              list of the filesystems may be replaced by --types umount

       -A, --all-targets
              Unmount all mountpoints in the current mount namespace for the
              specified filesystem.  The filesystem can be specified by one
              of the mountpoints or the device name (or UUID, etc.).  When
              this option is used together with --recursive, then all nested
              mounts within the filesystem are recursively unmounted.  This
              option is only supported on systems where /etc/mtab is a
              symlink to /proc/mounts.

       -c, --no-canonicalize
              Do not canonicalize paths.  The paths canonicalization is
              based on stat(2) and readlink(2) system calls. These system
              calls may hang in some cases (for example on NFS if server is
              not available). The option has to be used with canonical path
              to the mount point.

              For more details about this option see the mount(8) man page.
              Note that umount does not pass this option to the
              /sbin/umount.type helpers.

       -d, --detach-loop
              When the unmounted device was a loop device, also free this
              loop device. This option is unnecessary for devices
              initialized by mount(8), in this case "autoclear"
              functionality is enabled by default.

       --fake Causes everything to be done except for the actual system call
              or umount helper execution; this 'fakes' unmounting the
              filesystem.  It can be used to remove entries from the
              deprecated /etc/mtab that were unmounted earlier with the -n

       -f, --force
              Force an unmount (in case of an unreachable NFS system).

              Note that this option does not guarantee that umount command
              does not hang.  It's strongly recommended to use absolute
              paths without symlinks to avoid unwanted readlink and stat
              system calls on unreachable NFS in umount.

       -i, --internal-only
              Do not call the /sbin/umount.filesystem helper even if it
              exists.  By default such a helper program is called if it

       -l, --lazy
              Lazy unmount.  Detach the filesystem from the file hierarchy
              now, and clean up all references to this filesystem as soon as
              it is not busy anymore.

              A system reboot would be expected in near future if you're
              going to use this option for network filesystem or local
              filesystem with submounts.  The recommended use-case for
              umount -l is to prevent hangs on shutdown due to an
              unreachable network share where a normal umount will hang due
              to a downed server or a network partition. Remounts of the
              share will not be possible.

       -N, --namespace ns
              Perform umount in the mount namespace specified by ns.  ns is
              either PID of process running in that namespace or special
              file representing that namespace.

              umount(8) switches to the namespace when it reads /etc/fstab,
              writes /etc/mtab (or writes to /run/mount) and calls umount(2)
              system call, otherwise it runs in the original namespace.  It
              means that the target mount namespace does not have to contain
              any libraries or other requirements necessary to execute
              umount(2) command.

              See mount_namespaces(7) for more information.

       -n, --no-mtab
              Unmount without writing in /etc/mtab.

       -O, --test-opts option...
              Unmount only the filesystems that have the specified option
              set in /etc/fstab.  More than one option may be specified in a
              comma-separated list.  Each option can be prefixed with no to
              indicate that no action should be taken for this option.

       -q, --quiet
              Suppress "not mounted" error messages.

       -R, --recursive
              Recursively unmount each specified directory.  Recursion for
              each directory will stop if any unmount operation in the chain
              fails for any reason.  The relationship between mountpoints is
              determined by /proc/self/mountinfo entries.  The filesystem
              must be specified by mountpoint path; a recursive unmount by
              device name (or UUID) is unsupported.

       -r, --read-only
              When an unmount fails, try to remount the filesystem read-

       -t, --types type...
              Indicate that 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 indicate that no action should be taken
              for all of the mentioned types.  Note that umount reads
              information about mounted filesystems from kernel
              (/proc/mounts) and filesystem names may be different than
              filesystem names used in the /etc/fstab (e.g., "nfs4" vs.

       -v, --verbose
              Verbose mode.

       -V, --version
              Display version information and exit.

       -h, --help
              Display help text and exit.


       Normally, only the superuser can umount filesystems.  However, when
       fstab contains the user option on a line, anybody can umount the
       corresponding filesystem.  For more details see mount(8) man page.

       Since version 2.34 the umount command can be used to perform umount
       operation also for fuse filesystems if kernel mount table contains
       user's ID.  In this case fstab user= mount option is not required.

       Since version 2.35 umount command does not exit when user permissions
       are inadequate by internal libmount security rules.  It drops suid
       permissions and continue as regular non-root user.  This can be used
       to support use-cases where root permissions are not necessary (e.g.,
       fuse filesystems, user namespaces, etc).

LOOP DEVICE         top

       The umount command will automatically detach loop device previously
       initialized by mount(8) command independently of /etc/mtab.

       In this case the device is initialized with "autoclear" flag (see
       losetup(8) output for more details), otherwise it's necessary to use
       the option  --detach-loop or call losetup -d <device>. The autoclear
       feature is supported since Linux 2.6.25.


       The syntax of external unmount helpers is:

              umount.suffix {directory|device} [-flnrv] [-N namespace] [-t

       where suffix is the filesystem type (or the value from a uhelper= or
       helper= marker in the mtab file).  The -t option can be used for
       filesystems that have subtype support.  For example:

              umount.fuse -t fuse.sshfs

       A uhelper=something marker (unprivileged helper) can appear in the
       /etc/mtab file when ordinary users need to be able to unmount a
       mountpoint that is not defined in /etc/fstab (for example for a
       device that was mounted by udisks(1)).

       A helper=type marker in the mtab file will redirect all unmount
       requests to the /sbin/umount.type helper independently of UID.

       Note that /etc/mtab is currently deprecated and helper= and other
       userspace mount options are maintained by libmount.

ENVIRONMENT         top

              overrides the default location of the fstab file (ignored for

              overrides the default location of the mtab file (ignored for

              enables libmount debug output

FILES         top

              table of mounted filesystems (deprecated and usually replaced
              by symlink to /proc/mounts)

              table of known filesystems

              table of mounted filesystems generated by kernel.

HISTORY         top

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

SEE ALSO         top

       umount(2), losetup(8), mount_namespaces(7) mount(8)

AVAILABILITY         top

       The umount command is part of the util-linux package and is available
       from Linux Kernel Archive 

COLOPHON         top

       This page is part of the util-linux (a random collection of Linux
       utilities) project.  Information about the project can be found at 
       ⟨⟩.  If you have a
       bug report for this manual page, send it to  This page was obtained from the
       project's upstream Git repository
       ⟨git://⟩ on
       2020-09-18.  (At that time, the date of the most recent commit that
       was found in the repository was 2020-09-15.)  If you discover any
       rendering problems in this HTML version of the page, or you believe
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       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to

util-linux                        July 2014                        UMOUNT(8)

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