Session and utilities

The fuser command

Says which processes are using a file, a folder or a port. Very useful before unmounting a USB stick.

Syntax

fuser archivo | fuser -n tcp puerto

Most useful options

-n tcpQueries a TCP port
-kKills the processes using it
-vVerbose output

Copy-ready examples

$ printf 'x\n' > f.txt && fuser f.txtWho uses the file?

You can try them in the browser terminal: it does not touch your computer.

Typical mistakes

  • With -k it can close programs without warning: use it carefully.

Related commands

lsofumountss

FAQ

Why can I not unmount the USB?

Because fuser will tell you which process is using it.

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