Linux Survival Basics

Find Which Package Owns a File

You see a file or command on a Debian or Ubuntu host and need to identify the package that installed it.

Command

dpkg-query -S /usr/sbin/nginx

What changed

Nothing changes. dpkg-query searches the local package ownership database.

Danger

safe

When to use it

Use when auditing binaries, tracing config files, or deciding which package documentation to read.

When not to use it

Do not expect it to identify files copied manually outside the package database.

Undo or recovery

No undo needed because the command is read-only.

Expected output

A package-to-path mapping such as nginx: /usr/sbin/nginx.

demo script

Disposable terminal steps

dpkg-query -S /usr/sbin/nginx
dpkg-query -S /usr/bin/curl

Terminal transcript Demo JSON

simulated output

What it looks like

disposable vessel

::fixture-ready::
$ dpkg-query -S /usr/sbin/nginx
nginx: /usr/sbin/nginx
::exit-code::0
$ dpkg-query -S /usr/bin/curl
curl: /usr/bin/curl
::exit-code::0

YouTube Short

Find a file's package.

If you find a binary on a Debian system, ask dpkg which package owns that path before guessing.

experiments

A/B tests to run

Metric: save_rate

A: Which package owns this file?

B: Trace binaries before touching them.