umount Command

The umount command enables you to remove a remote file system that is currently mounted. You can use the following options with the umount command:

-V

Enables testing

-a

Unmounts several file systems at one time. If mount-points are included with the -a option, those file systems are unmounted. If no mount points are included, an attempt is made to unmount all file systems that are listed in /etc/mnttab except for the "required" file systems, such as /, /usr, /var, /proc, /dev/fd, and /tmp. Because the file system is already mounted and should have an entry in /etc/mnttab, you do not need to include a flag for the file system type.

-f

Forces a busy file system to be unmounted. You can use this option to unhang a client that is hung while trying to mount an unmountable file system.

Caution:

By forcing an unmount of a file system, you can cause data loss if files are being written to that system.

Example 5-1 Unmounting a File System

The following example unmounts a file system that is mounted on /usr/man:

# umount /usr/man

Example 5-2 Using Options with umount

The following example displays the results of running umount -a -V:

# umount -a -V
umount /home/kathys
umount /opt
umount /home
umount /net

Note that this command does not actually unmount the file systems.