apt-get

Update the list of available packages and versions (it's recommended to run this before other apt-get commands)

$ sudo apt-get update

$ sudo apt-get install [package]

$ sudo apt-get remove [package]

$ sudo apt-get purge [package]

$ sudo apt-get upgrade

$ sudo apt-get autoclean

$ sudo apt-get autoremove

$ sudo apt-get dist-upgrade

apt-get [options] command [package ...]

-h, --help
    Show summary of options.

-v, --version
    Show version information.

-q, --quiet
    Produce less output; repeat for more quiet.

-y, --assume-yes, --assume-y
    Assume 'yes' to all prompts.

-d, --download-only
    Download packages but do not install.

-s, --simulate, --dry-run, --recon, --just-print
    Simulate actions without changes.

-u, --upgrade
    Show upgraded packages (with install/upgrade).

-b, --build
    Build source packages only.

-V, --verbose-versions
    Explain versions during install.

--allow-downgrades
    Allow downgrading packages.

--allow-remove-essential
    Allow removing essential packages.

--allow-change-held-packages
    Allow changes to held packages.

--no-install-recommends
    Do not install recommended packages.

--install-recommends
    Install recommended packages too.

--only-source
    Get source packages only.

--only-deb
    Get deb packages only.

--no-upgrade
    Do not upgrade packages.

--no-remove
    Do not remove packages.

--ignore-missing
    Ignore missing packages.

-t, --target-release, -T
    Target release version.

-o, --option
    Set custom configuration option.

-c, --config-file
    Use alternative config file.

-a, --architectures
    Process architectures.

apt-get is a powerful command-line tool for managing packages on Debian-based systems like Ubuntu. Part of the APT (Advanced Package Tool) suite, it handles installing, updating, upgrading, removing, and querying software packages from remote repositories defined in /etc/apt/sources.list and /etc/apt/sources.list.d/.

It fetches package lists with update, installs or upgrades with install or upgrade, and cleans up with clean or autoremove. Designed for scripts and advanced users, it requires superuser privileges (use sudo). Unlike graphical tools, it provides precise control over dependencies, versions, and simulations.

Key strengths include handling complex dependency resolution, source code compilation via source, and holding packages. It's script-friendly with options like --assume-yes for automation. While apt offers a user-friendly wrapper, apt-get remains essential for servers and precise operations, supporting both binary (.deb) and source packages.

Requires root privileges (sudo); can break system if misused (e.g., removing essentials); repositories must be updated first; prefer apt for interactive use as apt-get is script-oriented.

update: Refresh package lists.
upgrade: Upgrade installed packages.
dist-upgrade: Upgrade with package additions/removals.
install: Install packages.
remove: Remove packages (keep config).
purge: Remove packages and config.
autoremove: Remove unused deps.
clean: Clear downloaded .deb files.

Main: /etc/apt/sources.list
Extras: /etc/apt/sources.list.d/*.list
Use apt-get update after editing.

Developed as part of APT by Debian's Jason Gunthorpe and Fabrice Bellet; first released in 1998 with APT 0.1.9 for better dependency handling over dpkg. Evolved through decades, key in Ubuntu since 2004; largely stable, with apt (2014) as modern frontend.

apt(8), apt-cache(8), dpkg(1), aptitude(8), synaptic(8)