commands-flat/check-apt-health.md

APT Package Manager Health Check

You are helping the user ensure that the APT package manager on Ubuntu is in good working health and remove any broken third-party repositories or packages.

Your tasks:

1. Check basic APT functionality:

   • Update package lists: sudo apt update
   • Check for errors in output
   • Verify cache state: apt-cache policy

2. Check for broken packages:

   • List broken packages: dpkg -l | grep "^..r"
   • Check for unconfigured packages: dpkg -l | grep "^..c"
   • Check dpkg status: sudo dpkg --configure -a
   • Check for broken dependencies: sudo apt-get check

3. Identify problematic repositories:

   • List all repositories:

     grep -r --include '*.list' '^deb ' /etc/apt/sources.list /etc/apt/sources.list.d/
     

   • Check for failing repositories during update:

     sudo apt update 2>&1 | grep -i "fail\|error\|warning"
     

   • List third-party PPAs:

     ls /etc/apt/sources.list.d/
     

4. Check APT cache integrity:

   • Check cache size: du -sh /var/cache/apt/archives/
   • List problematic cache entries:

     sudo apt-get clean
     sudo apt-get autoclean
     

5. Fix broken dependencies:

   • Attempt to fix broken packages:

     sudo apt --fix-broken install
     

   • Force reconfiguration of all packages:

     sudo dpkg --configure -a
     

   • Try to complete interrupted installations:

     sudo apt-get -f install
     

6. Identify and handle broken third-party repositories: For each failing repository found:

   • Ask user if they still need it
   • If not needed, disable or remove:

     sudo add-apt-repository --remove ppa:<ppa-name>
     

   • Or manually remove: sudo rm /etc/apt/sources.list.d/<repo>.list
   • Or disable by commenting out: sudo sed -i 's/^deb/#deb/' /etc/apt/sources.list.d/<repo>.list

7. Check for GPG key issues:

   • Check for missing GPG keys:

     sudo apt update 2>&1 | grep "NO_PUBKEY"
     

   • If missing keys found, attempt to import:

     sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys <KEY>
     

   • List all trusted keys: apt-key list

8. Check for duplicate repositories:

   • Find duplicates:

     grep -h "^deb " /etc/apt/sources.list /etc/apt/sources.list.d/* | sort | uniq -d
     

   • Remove duplicates manually or ask user which to keep

9. Check disk space:

   • Disk space in /var: df -h /var
   • If low on space:

     sudo apt-get clean
     sudo apt-get autoclean
     sudo apt-get autoremove
     

10. Check for held packages:

    • List held packages: apt-mark showhold
    • These packages won't be upgraded - ask user if intentional
    • To unhold: sudo apt-mark unhold <package-name>

11. Verify repository configurations:

    • Check main sources.list: cat /etc/apt/sources.list
    • Ensure official Ubuntu repositories are present:
      • main
      • restricted
      • universe
      • multiverse
      • security updates
      • updates
      • backports (optional)

12. Check for obsolete packages:

    • List locally installed packages not in any repository:

      aptitude search '~o'
      

    • Or using apt: apt list '~o'

13. Verify package authentication:

    • Check if packages are being verified:

      grep -r "APT::Get::AllowUnauthenticated" /etc/apt/
      

    • Should be "false" or not present for security

14. Run full system check:

    • Check for consistency: sudo apt-get check
    • Simulate upgrade to check for issues: sudo apt-get -s upgrade
    • Simulate dist-upgrade: sudo apt-get -s dist-upgrade

15. Clean up:

    • Remove old packages: sudo apt-get autoremove
    • Clean package cache: sudo apt-get clean
    • Clean old cached packages: sudo apt-get autoclean

16. Reset APT if severely broken: If APT is severely corrupted, may need to:

    # Backup current sources
    sudo cp -r /etc/apt /etc/apt.backup
    
    # Reset dpkg
    sudo dpkg --clear-avail
    sudo apt-get update
    
    # Reinstall base packages if needed
    sudo apt-get install --reinstall apt dpkg
    

17. Check APT configuration files:

    • List all APT config: apt-config dump
    • Check for problematic configurations in:
      • /etc/apt/apt.conf
      • /etc/apt/apt.conf.d/
    • Look for unusual proxy settings, deprecated options

18. Report findings: Summarize:

    • Number of broken packages (if any)
    • Problematic repositories (outdated PPAs, failing repos)
    • Missing GPG keys
    • Dependency issues
    • Disk space issues
    • Held packages
    • Overall APT health status (HEALTHY / NEEDS ATTENTION / BROKEN)

19. Provide recommendations:

    • List of repositories to remove
    • Packages to fix or remove
    • Whether full system upgrade is recommended
    • Cleanup commands to run
    • Any configuration changes needed
    • If APT is healthy, suggest regular maintenance:

      sudo apt update && sudo apt upgrade
      sudo apt autoremove
      sudo apt clean
      

Important notes:

• Always backup before removing repositories or packages
• Don't remove dependencies of packages user needs
• Some third-party repos may be intentionally added - confirm before removing
• Be cautious with --fix-broken - it may remove packages
• Check if user is running unsupported Ubuntu version (EOL)
• PPAs may lag behind Ubuntu releases
• sudo is required for most operations
• After major fixes, suggest reboot to ensure clean state