umount Command

This command enables you to remove a remote file system that is currently mounted. The umount command supports the -V option to allow for testing. You might also use the -a option to unmount 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.

The -f option 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.

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

See the following examples.

Example 6–1 Unmounting a File System

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

# umount /usr/man

Example 6–2 Using Options with umount

This example displays the results of running umount -a -V:

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

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