Disk
umount
Unmount a mounted filesystem to safely detach it.
Synopsis
syntax
umount [OPTION]... DIRECTORY|DEVICE
Examples
Unmount a USB drive
sudo umount /mnt/usb
Lazy unmount a busy filesystem
sudo umount -l /mnt/stuck
Unmount by device name
sudo umount /dev/sdb1
Common options
| Flag | Description |
|---|---|
| -l | Lazy unmount — detach now, clean up later |
| -f | Force unmount (for unreachable NFS) |
| -a | Unmount all |
| -R | Recursively unmount |
About umount
The `umount` command unmount a mounted filesystem to safely detach it. Disk commands handle low-level storage operations including partitioning, formatting, filesystem checks, and block device management.
These tools are critical during system installation, storage expansion, data recovery, and performance tuning. Always exercise caution — disk operations can cause data loss if used incorrectly.
The command accepts 4 commonly used flags shown above, though the full set of options is available in the man page (`man umount`). The 3 examples on this page cover typical real-world usage patterns that you can copy and adapt for your own workflows.
Related commands
More Disk Commands
Other commands in the Disk category