Advanced package tool, or APT, is a free-software user interface that works with core libraries to handle the installation and removal of software on Debian and Debian-based Linux distributions.

apt vs. apt-get

Task apt command apt-get command
Update package list apt update apt-get update
Upgrade all upgradable packages apt upgrade apt-get upgrade
Install a new package apt install [package] apt-get install [package]
Remove a package apt remove [package] apt-get remove [package]
Remove a package along with configuration files apt purge [package] apt-get purge [package]
Search for a package apt search [package] apt-cache search [package]
Show information about a package apt show [package] apt-cache show [package]
Clean up unused packages and cache apt autoremove and apt autoclean apt-get autoremove and apt-get autoclean