Lesson 13: Package Management

Goal: Learn to install, update, and manage software on Linux using different package managers.

Table of Contents

1. apt — Debian/Ubuntu
2. nala — Modern apt Frontend
3. dpkg — Low-Level Package Tool
4. snap — Universal Packages
5. flatpak — Desktop Applications
6. Homebrew — Cross-Platform
7. AppImages — Portable Apps
8. Comparing Package Formats
9. Exercises

apt — Debian/Ubuntu

apt is the standard package manager for Debian-based distributions (Ubuntu, Mint, Pop!_OS).

Update package lists

# Always run this first to get the latest package info
sudo apt update

Upgrade installed packages

# Upgrade all packages
sudo apt upgrade

# Upgrade with automatic dependency resolution
sudo apt full-upgrade

# Combine update + upgrade
sudo apt update && sudo apt upgrade -y

Install packages

# Install a single package
sudo apt install nginx

# Install multiple packages
sudo apt install git curl wget htop

# Install without confirmation
sudo apt install -y docker.io

# Install a specific version
sudo apt install nginx=1.18.0-0ubuntu1

Remove packages

# Remove package (keep config files)
sudo apt remove nginx

# Remove package AND config files
sudo apt purge nginx

# Remove unused dependencies
sudo apt autoremove

# Complete cleanup
sudo apt purge nginx && sudo apt autoremove

Search and info

# Search for packages
apt search "web server"

# Show package details
apt show nginx

# List installed packages
apt list --installed

# List upgradable packages
apt list --upgradable

# Check if a package is installed
apt list --installed | grep nginx

Cache management

# Show cache size
sudo du -sh /var/cache/apt/

# Clean downloaded packages
sudo apt clean

# Remove old versions from cache
sudo apt autoclean

nala — Modern apt Frontend

nala is a modern, user-friendly frontend for apt with better output and parallel downloads.

Install nala

sudo apt install nala

Usage (same as apt, just replace apt with nala)

# Update
sudo nala update

# Install
sudo nala install htop

# Upgrade
sudo nala upgrade

# Remove
sudo nala remove htop

# Search
nala search "text editor"

# Show package info
nala show vim

# History of all operations
nala history

Advantages of nala

• Cleaner, more readable output
• Parallel downloads (faster installs)
• Transaction history with undo
• Better dependency resolution display

Undo operations

# Show history
nala history

# Undo a specific operation
sudo nala history undo 5

Pick the fastest mirrors

sudo nala fetch
# Selects the 3 fastest mirrors for your location

dpkg — Low-Level Package Tool

dpkg manages individual .deb files directly.

# Install a .deb file
sudo dpkg -i package.deb

# If dependencies are missing, fix them
sudo apt install -f

# Remove a package
sudo dpkg -r package-name

# Purge (remove + config)
sudo dpkg -P package-name

# List all installed packages
dpkg -l

# Search installed packages
dpkg -l | grep nginx

# List files installed by a package
dpkg -L nginx

# Find which package owns a file
dpkg -S /usr/bin/curl

snap — Universal Packages

Snaps are containerized packages that work across distributions.

Install snapd

sudo apt install snapd

Basic usage

# Search for snaps
snap find "visual studio"

# Install a snap
sudo snap install code --classic

# List installed snaps
snap list

# Show snap info
snap info code

# Update all snaps
sudo snap refresh

# Remove a snap
sudo snap remove code

Classic vs strict confinement

# Strict: sandboxed, limited system access
sudo snap install firefox

# Classic: full system access (like apt)
sudo snap install code --classic

flatpak — Desktop Applications

Flatpak is another universal package format, popular for desktop applications.

Install flatpak

sudo apt install flatpak

# Add Flathub repository
flatpak remote-add --if-not-exists flathub https://dl.flathub.org/repo/flathub.flatpakrepo

Basic usage

# Search for apps
flatpak search firefox

# Install from Flathub
flatpak install flathub org.mozilla.firefox

# List installed apps
flatpak list

# Run an app
flatpak run org.mozilla.firefox

# Update all apps
flatpak update

# Remove an app
flatpak uninstall org.mozilla.firefox

# Clean up unused runtimes
flatpak uninstall --unused

Manage permissions — Flatseal

flatpak install flathub com.github.tchx84.Flatseal

Flatseal provides a GUI to manage Flatpak app permissions.

Homebrew — Cross-Platform

Homebrew (originally macOS) also works on Linux for installing developer tools.

Install Homebrew

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"

Add to PATH (after install)

echo 'eval "$(/home/linuxbrew/.linuxbrew/bin/brew shellenv)"' >> ~/.bashrc
source ~/.bashrc

Basic usage

# Install a package
brew install node

# Search
brew search python

# Update Homebrew itself
brew update

# Upgrade all packages
brew upgrade

# Info about a package
brew info node

# List installed packages
brew list

# Remove a package
brew uninstall node

# Cleanup old versions
brew cleanup

AppImages — Portable Apps

AppImages are single-file portable applications. No installation needed.

Using an AppImage

# 1. Download the AppImage
wget https://example.com/app.AppImage

# 2. Make it executable
chmod +x app.AppImage

# 3. Run it
./app.AppImage

Integrate with system

# Move to a standard location
mkdir -p ~/Applications
mv app.AppImage ~/Applications/

# Create a desktop entry for menu integration
cat > ~/.local/share/applications/myapp.desktop << EOF
[Desktop Entry]
Name=My App
Exec=$HOME/Applications/app.AppImage
Type=Application
Categories=Utility;
EOF

Comparing Package Formats

Recommendation

• System packages (nginx, git, curl) → apt
• Desktop applications (Firefox, GIMP) → flatpak
• Developer tools (node, python) → apt or brew
• Portable/testing → AppImage

Exercises

Exercise 1: apt basics

# 1. Update package lists
sudo apt update

# 2. Search for a package
apt search "terminal emulator"

# 3. Show info about a package
apt show htop

# 4. Check what can be upgraded
apt list --upgradable

# 5. Clean the package cache
sudo apt clean

Exercise 2: Install and remove

# 1. Install a small package
sudo apt install -y cowsay

# 2. Use it
cowsay "Hello Linux!"

# 3. Find where it was installed
which cowsay
dpkg -L cowsay

# 4. Remove it completely
sudo apt purge -y cowsay && sudo apt autoremove -y

Exercise 3: Try nala

# 1. Install nala
sudo apt install -y nala

# 2. Fetch fastest mirrors
sudo nala fetch

# 3. Install something with nala
sudo nala install -y tree

# 4. Check history
nala history

Key Takeaways

• sudo apt update && sudo apt upgrade — keep your system up to date
• apt install / apt remove — install/remove packages
• nala — better apt experience with parallel downloads
• dpkg -i file.deb — install individual .deb files
• snap — sandboxed universal packages
• flatpak — desktop apps from Flathub
• AppImages — portable, no-install applications
• Always apt update before apt install

Next Lesson: Lesson 14: Process Management →