LOW risk. With -k flag, can send signals to processes.

fuser

Q: What does fuser do?

Identify processes using files or sockets. fuser identifies which processes are using specified files, directories, or network sockets. Simpler than lsof for the specific question 'what is using this file/port?' Returns PIDs which can be targeted directly.

Identify processes using files or sockets.

low risk

interactive breakdown — edit the command and press Explain

What it does

fuser identifies which processes are using specified files, directories, or network sockets. Simpler than lsof for the specific question 'what is using this file/port?' Returns PIDs which can be targeted directly.

Common flags

Flag	Meaning
`-v` `--verbose`	Verbose output including username and access type
`-n` `--namespace`	Select namespace: file, tcp, udp
`-k` `--kill`	Kill processes (sends SIGKILL by default)
`-m` `--mount`	All processes accessing the mount point

Examples

fuser 8080/tcpFind PID using TCP port 8080 · explain & risk-check →

fuser -v /var/log/app.logVerbose: show who has log file open · explain & risk-check →

fuser -k 8080/tcpKill process using port 8080 · explain & risk-check →

fuser -m /mnt/dataFind all processes accessing a mounted volume · explain & risk-check →

Pro tip

Before `umount` fails with 'device is busy', run `fuser -mv /mountpoint` to find exactly which process is holding the mount — saves the 'why can't I unmount this' frustration.

lsof ss kill

Open the full explainer →More in System & Processes

Reference text is hand-written and may be incomplete — check man fuser for your version. Test destructive commands on a non-production system first.