umount

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 umount 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 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 command cannot succeed if the file system is in use. For instance, if a user has used cd to get access to a file system, the file system is busy until the working directory is changed. The umount command can hang temporarily if the NFS server is unreachable.

Using the umount Command

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

# umount /usr/man

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.