umount

Unlink a filesystem from its mount point, making it no longer accessible. A filesystem cannot be unmounted when it is busy. More information: https://manned.org/umount.8.

Unmount a filesystem, by passing the path to the source it is mounted from:

umount {{path/to/device_file}}

Unmount a filesystem, by passing the path to the target where it is mounted:

umount {{path/to/mounted_directory}}

Unmount all mounted filesystems (except the proc filesystem):

umount -a