Linux Survival Basics

See Which Packages Want Updates

You need to see pending package updates without changing the system.

Command

apt list --upgradable

What changed

Nothing changes. The command reads apt metadata and prints packages with newer candidate versions.

Danger

safe

When to use it

Use before maintenance windows, security patch review, or explaining why a host is behind.

When not to use it

Do not assume this refreshes repository metadata; apt update is a separate state-changing network operation.

Undo or recovery

No undo needed because the command is read-only.

Expected output

Apt rows showing package names, candidate versions, architectures, and installed versions.

demo script

Disposable terminal steps

apt list --upgradable
apt list --upgradable 2>/dev/null | sed -n '2,$p'

Terminal transcript Demo JSON

simulated output

What it looks like

disposable vessel

::fixture-ready::
$ apt list --upgradable
Listing... Done
curl/noble-updates 8.5.0-2ubuntu10.7 amd64 [upgradable from: 8.5.0-2ubuntu10.6]
openssl/noble-updates,noble-security 3.0.13-0ubuntu3.6 amd64 [upgradable from: 3.0.13-0ubuntu3.5]
nginx/noble-updates 1.24.0-2ubuntu7.4 amd64 [upgradable from: 1.24.0-2ubuntu7.3]
::exit-code::0
$ apt list --upgradable 2>/dev/null | sed -n '2,$p'
curl/noble-updates 8.5.0-2ubuntu10.7 amd64 [upgradable from: 8.5.0-2ubuntu10.6]
openssl/noble-updates,noble-security 3.0.13-0ubuntu3.6 amd64 [upgradable from: 3.0.13-0ubuntu3.5]
nginx/noble-updates 1.24.0-2ubuntu7.4 amd64 [upgradable from: 1.24.0-2ubuntu7.3]
::exit-code::0

YouTube Short

List updates first.

Do not start with upgrade. First list the packages that would move and capture the installed versions.

experiments

A/B tests to run

Metric: save_rate

A: List before upgrade.

B: What would apt change?