Command documentation sourced from the linux-command project This comprehensive command reference is part of the linux-command documentation project.

apt - Advanced Package Tool

The apt command is a high-level interface for the package management system used in Debian-based Linux distributions. It serves as a user-friendly replacement for apt-get and provides simplified commands for managing software packages, including installation, updates, and removal operations.

Basic Syntax

apt [OPTIONS] COMMAND

Common Options

General Options

• -h, --help - Display help information
• -v, --version - Display apt version
• -c, --config-file FILE - Read configuration file
• -o, --option OPTION=VALUE - Set a configuration option

Common Command Options

• -y, --yes - Assume "yes" to all prompts
• -q, --quiet - Quiet mode, minimal output
• -s, --simulate, --dry-run - Simulate the command without making changes
• -d, --download-only - Download packages without installing or configuring
• -f, --fix-broken - Attempt to fix broken dependencies

Usage Examples

Basic Package Management

# Update package lists from repositories
apt update

# Upgrade all installed packages to latest versions
apt upgrade

# Perform full system upgrade (may install/remove packages)
apt full-upgrade

# Install a new package
apt install package_name

# Install multiple packages
apt install package1 package2 package3

# Remove a package (keep configuration files)
apt remove package_name

# Remove a package and its configuration files
apt purge package_name

# Remove automatically installed unused packages
apt autoremove

Package Information and Search

# Search for packages by name or description
apt search search_term

# Show detailed information about a package
apt show package_name

# Show package information in a specific format
apt show --no-all-versions package_name

# List installed and available packages
apt list

# List only installed packages
apt list --installed

# List only upgradable packages
apt list --upgradable

# List all available versions of a package
apt list --all-versions package_name

Package Source and Repository Management

# Add a new repository
apt add-repository repository_specification

# Remove a repository
apt add-repository -r repository_specification

# Edit sources list
apt edit-sources

Cache and Maintenance Operations

# Clean the package cache completely
apt clean

# Remove obsolete package cache files
apt autoclean

# Verify there are no broken dependencies
apt check

# Download a package without installing
apt download package_name

# Reinstall a package
apt install --reinstall package_name

Practical Examples

System Maintenance and Updates

# Complete system update routine
apt update && apt upgrade -y && apt autoremove -y && apt autoclean

# Check for broken packages and fix them
apt check
apt install --fix-broken

# Update specific package categories
apt update && apt install --only-upgrade security-updates

Package Installation and Management

# Install package with specific version
apt install package_name=version_number

# Install package without recommended packages
apt install --no-install-recommends package_name

# Install package including recommended packages
apt install --install-recommends package_name

# Install package from specific repository
apt install -t repository_name package_name

# Hold a package to prevent updates
apt-mark hold package_name

# Unhold a package to allow updates
apt-mark unhold package_name

# Show why a package cannot be installed
apt policy package_name

# Show package dependencies
apt depends package_name

# Show reverse dependencies
apt rdepends package_name

Package Information and Debugging

# Show package details including dependencies
apt-cache show package_name

# Show package statistics
apt-cache stats

# Search package names and descriptions
apt-cache search keyword

# Find packages that provide a specific file
apt-file search filename

# Show files included in a package
apt-file list package_name

# Update apt-file database
apt-file update

System Package State Analysis

# List all installed packages with versions
apt list --installed

# List upgradable packages with version information
apt list --upgradable

# Show pending changes without executing
apt dist-upgrade -s

# Check which packages were recently installed
apt history log

# Show detailed command history
apt history

# Undo a specific apt operation
apt history undo number

# Rollback to a specific system state
apt history rollback number

Advanced Package Operations

# Download source code for a package
apt source package_name

# Build dependencies for a package
apt build-dep package_name

# Change package priorities
apt-cache policy package_name

# Satisfy dependency requirements
apt satisfy "dependency_expression"

# Mark package as automatically installed
apt-mark auto package_name

# Mark package as manually installed
apt-mark manual package_name

# Show package manual/auto status
apt-mark showmanual
apt-mark showauto

Repository and Source Management

# Add PPA repository (Ubuntu)
apt add-repository ppa:user/repository

# Add repository with GPG key
apt-add-repository 'deb [arch=amd64] https://repo.example.com/ focal main'

# Update repository keys
apt-key update

# Add repository GPG key
apt-key add keyfile.asc

# Remove repository GPG key
apt-key del key_id

# List trusted keys
apt-key list

Package Cache Operations

# Show cache statistics
apt-cache stats

# Show cache size
apt-cache showpkg package_name

# Clean only specific cache directories
apt-get clean -o Dir::Cache::archives=/path/to/cache

# Configure cache retention
apt-get autoclean -o APT::Clean-Installed="true"

Related Commands

• apt-get - Low-level package handling utility (legacy)
• apt-cache - Package cache query tool
• apt-file - Search for files in packages
• apt-key - APT repository key management
• apt-mark - Package selection state management
• dpkg - Low-level package manager
• aptitude - Text-based package management interface
• sources.list - Repository configuration file

Best Practices

System Updates

1. Always run apt update before installing or upgrading packages
2. Use apt upgrade for regular updates and full-upgrade for major system changes
3. Schedule regular system updates using cron or systemd timers
4. Test updates on staging systems before production deployment

Package Management

1. Use autoremove regularly to clean up unused dependencies
2. Consider using --no-install-recommends for minimal installations
3. Use apt-mark hold to prevent unwanted updates of critical packages
4. Verify package integrity before installation using apt-cache show

Security Considerations

1. Always verify repository authenticity before adding new sources
2. Regularly update package lists to receive security patches
3. Use apt-listchanges to review changelog information
4. Consider using unattended-upgrades for automated security updates

Performance Optimization

1. Configure apt mirrors for faster downloads
2. Use local package caches for multiple systems
3. Clean package cache regularly with autoclean
4. Consider using apt-fast or similar tools for parallel downloads

Troubleshooting

1. Use apt check to identify broken dependencies
2. Fix broken packages with --fix-broken option
3. Review /var/log/apt/history.log for installation history
4. Use apt policy to understand package version and repository priority
5. Check network connectivity and DNS resolution for repository access issues

Configuration Management

1. Use /etc/apt/apt.conf.d/ for custom apt configuration
2. Configure proxy settings if needed for repository access
3. Set up repository priorities for mixed-source environments
4. Use pinning to control package version preferences

The apt command provides a modern, user-friendly interface for package management in Debian-based systems, combining the functionality of multiple legacy tools while offering improved usability and better dependency resolution capabilities.