fuser

Additional Notes

fuser is a process-management command used to identify processes using files, directories, or sockets. It identifies which processes have a file, directory, or socket open. It is commonly used to find why a filesystem cannot be unmounted or which process is using a network port.

Syntax

fuser [options] file|mount|port

Parameters

• options: Flags that change how fuser behaves.
• target: File, mount point, filesystem, or port to inspect.

Common Options

• -v: Verbose output.
• -k: Kill processes using the target.
• -n tcp PORT: Check a TCP port.
• -m PATH: Check a mounted filesystem.

Examples

fuser -v /mnt/usb
fuser -n tcp 8080
sudo fuser -k /mnt/usb

Practical Notes

Use fuser to find why a mount cannot be unmounted or why a port is busy.