System Administration · #11 of 19

Package Management

apt & Software Installation

What is a Package Manager?

A package manager is like an app store for the command line:

Downloads software from trusted repositories
Installs it in the right locations
Handles dependencies (libraries it needs)
Updates everything with one command
Removes software cleanly

Ubuntu uses APT (Advanced Package Tool).

The apt Command

Updating Package Lists

sudo apt update             # Refresh available packages
# This doesn't install anything — just updates the catalog

Upgrading Installed Packages

sudo apt upgrade            # Upgrade all packages
sudo apt full-upgrade       # Upgrade, including removals if needed

Installing Software

sudo apt install firefox    # Install Firefox
sudo apt install vim git    # Install multiple packages
sudo apt install ./package.deb  # Install local .deb file

Removing Software

sudo apt remove firefox     # Remove package (keep config)
sudo apt purge firefox      # Remove package AND config files
sudo apt autoremove         # Remove unused dependencies

Finding Packages

Search

apt search "text editor"    # Search by keywords
apt search ^vim             # Packages starting with 'vim'

Package Information

apt show vim                # Details about a package
apt list --installed        # All installed packages
apt list --upgradable       # Packages with updates available

Check if Installed

dpkg -l | grep vim          # Search installed packages
which vim                   # Find where it's installed

Repository Management

Packages come from repositories (repos). Ubuntu has:

Main: Officially supported open source
Universe: Community-maintained open source
Restricted: Proprietary drivers
Multiverse: Software with restrictions

Adding Repositories

# Add a PPA (Personal Package Archive)
sudo add-apt-repository ppa:user/repo
sudo apt update

# Add third-party repo manually
sudo add-apt-repository "deb http://example.com/repo stable main"

Repository Configuration

cat /etc/apt/sources.list              # Main sources
ls /etc/apt/sources.list.d/            # Additional sources

Common Tasks

Update Everything

sudo apt update && sudo apt upgrade -y

Clean Up

sudo apt autoremove                    # Remove orphaned packages
sudo apt clean                         # Clear package cache

Fix Broken Packages

sudo apt --fix-broken install
sudo dpkg --configure -a

dpkg — Low-Level Tool

APT uses dpkg under the hood:

dpkg -l                     # List all installed packages
dpkg -i package.deb         # Install a .deb file
dpkg -r package             # Remove a package
dpkg -L vim                 # List files installed by vim
dpkg -S /usr/bin/vim        # Which package owns this file?

Other Package Formats

Snap

snap find vlc               # Search
snap install vlc            # Install
snap list                   # List installed snaps
snap remove vlc             # Remove

Flatpak

flatpak search gimp         # Search
flatpak install flathub org.gimp.GIMP   # Install
flatpak list                # List installed
flatpak uninstall org.gimp.GIMP         # Remove

Try It!

Practice package management in the terminal:

Exercises:

Update package lists: apt update (simulated)
Search for packages: apt search editor
Show package info: apt show vim
Install a package: apt install htop
List installed: apt list --installed

Try it in the terminal

A sandboxed shell with this lesson’s commands. Type help to see what’s available.

bash — try it

📦 Package Management