apt-get — Debian Package Manager

apt-get is a command-line package tool used on Debian-based Linux systems. It is commonly used to install, update, remove and search for software packages.

Update package information

sudo apt-get update

This refreshes the local package index. It does not upgrade packages by itself.

Install a package

sudo apt-get install package-name

Remove a package

sudo apt-get remove package-name

Upgrade installed packages

sudo apt-get upgrade

On modern systems, apt is often used interactively, while apt-get remains useful in scripts and older documentation.