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`	Search installed packages

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¶

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

Performance¶

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

Maintenance¶

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