APT Package Manager

Comprehensive APT (Advanced Package Tool) commands and workflows for Debian and Ubuntu package management.

Installation & Updates

Basic Package Operations

Command	Description
sudo apt update	Update package index
sudo apt upgrade	Upgrade all packages
sudo apt full-upgrade	Upgrade with dependency resolution
sudo apt install package_name	Install package
sudo apt remove package_name	Remove package
sudo apt purge package_name	Remove package and config files
sudo apt autoremove	Remove unused dependencies

Advanced Installation

Command	Description
sudo apt install package1 package2	Install multiple packages
sudo apt install package=version	Install specific version
sudo apt install ./package.deb	Install local .deb file
sudo apt reinstall package_name	Reinstall package
sudo apt install --no-install-recommends package	Install without recommended packages

Package Information

Search and Information

Command	Description
apt search keyword	Search for packages
apt show package_name	Show package information
apt list --installed	List installed packages
apt list --upgradable	List upgradable packages
apt list package_name	Check if package is available
dpkg -l	List all installed packages
`dpkg -l	grep package`

Package Dependencies

Command	Description
apt depends package_name	Show package dependencies
apt rdepends package_name	Show reverse dependencies
apt-cache policy package_name	Show package policy

Repository Management

Repository Operations

Command	Description
sudo add-apt-repository ppa:user/repo	Add PPA repository
sudo add-apt-repository --remove ppa:user/repo	Remove PPA repository
sudo apt edit-sources	Edit sources list
ls /etc/apt/sources.list.d/	List additional repositories

GPG Keys

Command	Description
sudo apt-key list	List GPG keys
wget -qO - https://example.com/key.gpg | sudo apt-key add -	Add GPG key
sudo apt-key del KEYID	Remove GPG key

System Maintenance

Cleanup Operations

Command	Description
sudo apt autoclean	Clean package cache
sudo apt clean	Remove all cached packages
sudo apt autoremove --purge	Remove unused packages and configs
sudo apt-get check	Check for broken dependencies

Fix Broken Packages

Command	Description
sudo apt --fix-broken install	Fix broken dependencies
sudo dpkg --configure -a	Configure unconfigured packages
sudo apt-get -f install	Force install to fix dependencies

Configuration Files

APT Configuration

File	Description
/etc/apt/sources.list	Main repository list
/etc/apt/sources.list.d/	Additional repository files
/etc/apt/apt.conf	APT configuration
/etc/apt/preferences	Package pinning

Example sources.list

# Ubuntu 22.04 LTS (Jammy Jellyfish)
deb http://archive.ubuntu.com/ubuntu/ jammy main restricted
deb http://archive.ubuntu.com/ubuntu/ jammy-updates main restricted
deb http://archive.ubuntu.com/ubuntu/ jammy universe
deb http://archive.ubuntu.com/ubuntu/ jammy-updates universe
deb http://archive.ubuntu.com/ubuntu/ jammy multiverse
deb http://archive.ubuntu.com/ubuntu/ jammy-updates multiverse
deb http://archive.ubuntu.com/ubuntu/ jammy-backports main restricted universe multiverse
deb http://security.ubuntu.com/ubuntu/ jammy-security main restricted
deb http://security.ubuntu.com/ubuntu/ jammy-security universe
deb http://security.ubuntu.com/ubuntu/ jammy-security multiverse

Package Pinning

Pin Package Version

# /etc/apt/preferences.d/package-pin
Package: package_name
Pin: version 1.2.3*
Pin-Priority: 1001

Pin Repository

# /etc/apt/preferences.d/repo-pin
Package: *
Pin: release o=Ubuntu,a=jammy-backports
Pin-Priority: 100

Advanced Usage

Simulation and Testing

Command	Description
apt list --upgradable -a	Show all available versions
sudo apt upgrade --dry-run	Simulate upgrade
sudo apt install package --dry-run	Simulate installation

Logging and History

Command	Description
cat /var/log/apt/history.log	View installation history
cat /var/log/apt/term.log	View detailed logs
grep " install " /var/log/dpkg.log	View dpkg install log

Troubleshooting

Common Issues

Problem	Solution
Package conflicts	sudo apt --fix-broken install
Locked database	sudo rm /var/lib/dpkg/lock*
Corrupted cache	sudo apt clean && sudo apt update
Unmet dependencies	sudo apt -f install

Emergency Recovery

Command	Description
sudo dpkg --force-depends --remove package	Force remove problematic package
sudo apt-get download package	Download package without installing
sudo dpkg -i --force-depends package.deb	Force install .deb file

Best Practices

Security

1. Regular Updates: Run sudo apt update && sudo apt upgrade regularly
2. Verify Sources: Only add trusted repositories
3. GPG Verification: Ensure packages are properly signed
4. Security Updates: Enable automatic security updates
5. Backup: Backup important data before major upgrades

Performance

1. Mirror Selection: Use fastest mirror for your location
2. Parallel Downloads: Enable parallel downloads in apt.conf
3. Cache Management: Regular cleanup of package cache
4. Dependency Resolution: Use apt instead of apt-get for better output
5. Network: Use reliable network connection for updates

Maintenance

1. Regular Cleanup: Remove unused packages and dependencies
2. Log Monitoring: Check logs for errors and warnings
3. Disk Space: Monitor disk space in /var/cache/apt/
4. Repository Health: Verify repository accessibility
5. System Consistency: Regular dependency checks