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umount(8) [freebsd man page]

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

NAME
umount -- unmount file systems SYNOPSIS
umount [-fv] special ... | node ... | fsid ... umount -a | -A [-F fstab] [-fv] [-h host] [-t type] DESCRIPTION
The umount utility calls the unmount(2) system call to remove a file system from the file system tree. The file system can be specified by its special device or remote node (rhost:path), the path to the mount point node or by the file system ID fsid as reported by ``mount -v'' when run by root. The options are as follows: -a All the file systems described in fstab(5) are unmounted. -A All the currently mounted file systems except the root are unmounted. -F fstab Specify the fstab file to use. -f The file system is forcibly unmounted. Active special devices continue to work, but all other files return errors if further accesses are attempted. The root file system cannot be forcibly unmounted. For NFS, a forced dismount can take up to 1 minute or more to complete against an unresponsive server and may throw away data not yet written to the server for this case. -h host Only file systems mounted from the specified host will be unmounted. This option implies the -A option and, unless otherwise speci- fied with the -t option, will only unmount NFS file systems. -t type Is used to indicate 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 for which action should not be taken. For example, the umount command: umount -a -t nfs,nullfs unmounts all file systems of the type NFS and NULLFS that are listed in the fstab(5) file. -v Verbose, additional information is printed out as each file system is unmounted. ENVIRONMENT
PATH_FSTAB If the environment variable PATH_FSTAB is set, all operations are performed against the specified file. PATH_FSTAB will not be honored if the process environment or memory address space is considered ``tainted''. (See issetugid(2) for more information.) FILES
/etc/fstab file system table SEE ALSO
unmount(2), fstab(5), autounmountd(8), mount(8) HISTORY
A umount utility appeared in Version 6 AT&T UNIX. BSD
November 22, 2014 BSD

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UMOUNT(8)						     Linux Programmer's Manual							 UMOUNT(8)

NAME
umount - unmount file systems SYNOPSIS
umount [-hV] umount -a [-dflnrv] [-t vfstype] [-O options] umount [-dflnrv] {dir|device}... DESCRIPTION
The umount command detaches the file system(s) mentioned from the file hierarchy. A file system is specified by giving the directory where it has been mounted. Giving the special device on which the file system 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 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. A lazy unmount avoids this problem. 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. -i Don't call the /sbin/umount.<filesystem> helper even if it exists. By default /sbin/umount.<filesystem> helper is called if one exists. -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 one option type may be specified in a comma separated list. Each option can be prefixed with no to specify options for which no action should be taken. -f Force unmount (in case of an unreachable NFS system). (Requires kernel 2.1.116 or later.) -l Lazy unmount. Detach the filesystem from the filesystem hierarchy now, and cleanup all references to the filesystem as soon as it is not busy anymore. (Requires kernel 2.4.11 or later.) --no-canonicalize Don't canonicalize paths. For more details about this option see the mount(8) man page. --fake Causes everything to be done except for the actual system call; this ``fakes'' unmounting the filesystem. It can be used to remove entries from /etc/mtab that were unmounted earlier with the -n option. 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). NOTES
The syntax of external umount helpers is: /sbin/umount.<suffix> {dir|device} [-nlfvr] [-t type.subtype] where the <suffix> is filesystem type or a value from "uhelper=" mtab option. The -t option is used for filesystems with subtypes support (for example /sbin/mount.fuse -t fuse.sshfs). The uhelper (unprivileged umount helper) is possible to used when non-root user wants to umount a mountpoint which is not defined in the /etc/fstab file (e.g devices mounted by HAL). 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. AVAILABILITY
The umount command is part of the util-linux package and is available from ftp://ftp.kernel.org/pub/linux/utils/util-linux/. Linux 2.0 26 July 1997 UMOUNT(8)

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