`sudo apt`

sudo apt <update|install|remove|upgrade> [package]

Risk: Careful

What it does

Finds, installs and removes programs from Debian's own store.

You need a tool the server does not have, or updates.

$ sudo apt install tree

Install the tree program.

$ sudo apt update

Refresh the shelf list first.

$ apt show tree

Read a package's label.

$ sudo apt remove tree

Take it off again.