Ubuntu handles software installation and updates through APT (Advanced Package Tool), a package management system that resolves dependencies automatically and fetches packages from a network of official mirrors. Under the hood, APT works with .deb packages — the Debian packaging format — and maintains a local index of all available software that you synchronize against remote repositories. Whether you’re installing a single utility or orchestrating a full system upgrade, the apt command is your primary tool. For lower-level operations like installing local .deb files or listing package state, you’ll reach for dpkg directly.
Updating Package Lists and Upgrading
Before installing or upgrading anything, refresh your local package index against the configured repositories. This ensures APT knows about the latest available versions.
sudo apt update # refresh package index from all configured sources
sudo apt upgrade # upgrade all installed packages to their latest version
sudo apt full-upgrade # upgrade with automatic dependency resolution (may add/remove packages)
sudo apt dist-upgrade # distribution upgrade, handles complex dependency changes
apt update does not install or upgrade anything — it only refreshes the index. You must follow it with apt upgrade (or apt install) to apply any changes.
Installing and Removing Packages
Install one or more packages by name. APT resolves and installs all required dependencies automatically.
sudo apt install nginx # install a single package
sudo apt install nginx curl git # install multiple packages at once
sudo apt remove nginx # remove a package but keep its configuration files
sudo apt purge nginx # remove a package and delete its configuration files
sudo apt autoremove # remove packages that were installed as dependencies and are no longer needed
Use apt purge instead of apt remove when you want a completely clean uninstall — for example, before reinstalling a service with a fresh configuration.
Searching for Packages
You can search the package index, view detailed metadata about a specific package, and inspect the state of installed packages — all without installing anything.
apt search nginx # search package names and descriptions for "nginx"
apt show nginx # display detailed metadata: version, dependencies, description
apt list --installed # list all currently installed packages
apt list --upgradable # list packages with available upgrades
Using dpkg Directly
dpkg is the low-level tool that APT builds on. You use it directly when you have a .deb file to install locally, or when you need granular information about installed packages.
sudo dpkg -i package.deb # install a local .deb file
dpkg -l # list all installed packages with status
dpkg -l | grep nginx # filter the installed list for a specific package
dpkg --get-selections # list all package selections (installed, deinstall, purge)
After running sudo dpkg -i package.deb, if APT reports missing dependencies, run sudo apt install -f to automatically resolve and install them.
Using apt-get (The Scriptable Interface)
apt-get is the older, lower-level counterpart to apt. It produces machine-parseable output with no progress bars or color — making it the preferred choice for shell scripts, Dockerfiles, and CI pipelines where predictable, unformatted output matters. The commands mirror apt closely.
sudo apt-get update # refresh the package index
sudo apt-get upgrade # upgrade all installed packages
sudo apt-get dist-upgrade # upgrade with automatic dependency resolution
sudo apt-get install nginx # install a package
sudo apt-get install -y nginx curl git # install multiple packages, auto-confirm prompts
sudo apt-get remove nginx # remove a package, keep configuration files
sudo apt-get purge nginx # remove a package and delete configuration files
sudo apt-get autoremove # remove unused dependency packages
sudo apt-get install -f # fix broken dependencies
In interactive terminals, prefer apt for its cleaner output and progress indicators. Use apt-get in scripts and automation where stable, parseable output is required — its output format is guaranteed not to change between Ubuntu releases.
Adding PPAs (Personal Package Archives)
PPAs let you install software maintained by community contributors that isn’t available in the official Ubuntu repositories. Add a PPA, update the index, then install as normal.
sudo add-apt-repository ppa:user/ppa-name # add the PPA and import its signing key
sudo apt update # refresh the index to include the new PPA
sudo apt install package-from-ppa # install the package from the PPA
PPAs are third-party sources and are not vetted by Canonical. Only add PPAs from publishers you trust, and prefer official repositories or snaps where they exist.
Snap Packages
Snaps are containerized software packages maintained by Canonical and app publishers. They bundle their own dependencies, update automatically, and work across Ubuntu versions.
snap find vlc # search the Snap Store for vlc
sudo snap install vlc # install a snap package
sudo snap remove vlc # remove an installed snap
snap list # list all installed snaps and their versions
sudo apt update
sudo apt install vlc
sudo apt remove vlc
apt-cache works offline and doesn’t require a recent apt update to query locally cached package data. Use apt-cache search nginx or apt-cache show nginx when you don’t have internet access but still need to inspect available packages.