APT (Advanced Package Tool) is the package manager for Debian and Debian-derived Linux distributions like Ubuntu, built and maintained by the Debian Project and free/open-source. It ties for #14 among dev tools in usage surveys at roughly 18.4% share. It's the everyday tool for installing, updating, and removing system software on a Debian-family server or desktop, resolving dependencies automatically from configured package repositories.
Refresh the package index, then install a piece of software — APT resolves and pulls in any dependencies automatically.
# refresh the list of available packages, then install nginx
sudo apt update && sudo apt install nginx
# upgrade every installed package to its latest version
sudo apt upgrade
# remove a package (keep config files)
sudo apt remove nginx
# search the package index
apt search postgresqlAPT comes preinstalled on every Debian and Ubuntu system — no separate setup is required, just start using it from a terminal.
# check APT is available (true on any Debian/Ubuntu box)
apt --version
# typical first commands on a fresh server
sudo apt update
sudo apt install build-essential git curl