umount
Detach filesystems from mount points
TLDR
SYNOPSIS
umount [options] target...
DESCRIPTION
umount detaches a filesystem from its mount point, making it no longer accessible. The filesystem can be specified by its source device or mount point directory.A filesystem cannot be unmounted while it is "busy" - that is, while files on it are open or processes have their working directory there. Use lsof or fuser to find processes using the filesystem.
PARAMETERS
-a, --all
Unmount all filesystems described in /etc/mtab (except proc).-A, --all-targets
Unmount all mountpoints in the current namespace for the specified filesystem.-r, --read-only
If unmount fails, try to remount read-only.-R, --recursive
Recursively unmount each specified directory.-l, --lazy
Lazy unmount: detach from the file hierarchy now, clean up references when no longer busy.-f, --force
Force unmount (for unreachable NFS mounts).-d, --detach-loop
Free the loop device if the unmounted device was a loop device.-n, --no-mtab
Don't write to /etc/mtab.-t, --types type
Unmount only filesystems of the specified type.-O, --test-opts opts
Unmount only filesystems with the specified options in /etc/fstab.-v, --verbose
Verbose mode.
CAVEATS
Requires root privileges unless the user option was specified in fstab. Busy filesystems cannot be unmounted normally. Lazy unmount (-l) can leave filesystem in inconsistent state. Force unmount (-f) only works for NFS. Part of the util-linux package.
HISTORY
umount has been a standard Unix command since the earliest versions, part of the util-linux package on Linux. The lazy unmount option (-l) was added in Linux 2.4.11.
