Use Debian Package Management Part 1

Debian’s native package manager, dpkg, handles the installation, upgrade, and removal of .deb packages on Debian‐based systems. In the early days of Linux, software was distributed as source archives (.tar.gz) requiring manual compilation. As distributions matured, package managers automated dependency resolution, file tracking, and version control. This article covers the fundamentals of using dpkg to:

Install and upgrade packages
Handle dependencies
Remove or purge packages
Force operations (with caution)
Inspect package contents and metadata
Reconfigure installed packages

Whether you’re a sysadmin automating deployments or a developer packaging your own software, understanding dpkg is essential for reliable Debian system management.

1. Installing and Upgrading Packages

To install a new .deb file or upgrade an existing one:

sudo dpkg -i mypackage.deb

If no version is installed, dpkg adds a fresh copy.
If an older version exists, it upgrades in place.

Note

For automated dependency resolution, consider using apt or apt-get instead.
sudo apt install ./mypackage.deb will fetch missing dependencies automatically.

Handling Dependency Errors

When dependencies are missing, dpkg aborts and lists unmet requirements:

sudo dpkg -i openshot-qt_2.4.3+dfsg1-1_all.deb

Sample output:

dpkg: dependency problems prevent configuration of openshot-qt:
 openshot-qt depends on fonts-cantarell; however:
  Package fonts-cantarell is not installed.
 ...
dpkg: error processing package openshot-qt (--install):
 dependency problems - leaving unconfigured

You must install each required .deb manually or switch to apt for automatic resolution.

2. Removing and Purging Packages

2.1 Remove (keep configuration files)

sudo dpkg -r unrar

dpkg checks reverse dependencies and refuses removal if other packages rely on it:

sudo dpkg -r p7zip

dpkg: dependency problems prevent removal of p7zip:
 winetricks depends on p7zip; however:
  Package p7zip is to be removed.
 ...

To remove multiple packages at once:

sudo dpkg -r unrar p7zip

2.2 Purge (remove package and configuration)

sudo dpkg -P unrar p7zip

Purging deletes all configuration files, freeing up disk space and resetting system state.

3. Forcing Operations

You can bypass dependency and safety checks—but this can break your system!

sudo dpkg -i --force-depends openshot-qt_2.4.3+dfsg1-1_all.deb

Use --force-all to override nearly all safeguards. Only force when you understand the implications.

Warning

Forcing package operations may lead to an inconsistent system state. Always have backups and test in a sandbox before using on production.

4. Inspecting Packages

Here’s a quick reference for common dpkg inspection commands:

Command	Description
`dpkg -I mypackage.deb`	Show metadata (version, maintainer, deps)
`dpkg --get-selections`	List all installed packages
`dpkg -L unrar`	List files installed by a package
`dpkg-query -S /usr/bin/unrar*`	Find which package owns a given file

4.1 View Package Metadata

dpkg -I mypackage.deb

4.2 List Files in a Package

sudo dpkg -L unrar

Sample output:

/usr/bin/unrar-nonfree
/usr/share/doc/unrar/changelog.Debian.gz
/usr/share/man/man1/unrar-nonfree.1.gz

4.3 Identify Owning Package of a File

dpkg-query -S /usr/bin/unrar-nonfree

Output:

unrar: /usr/bin/unrar-nonfree

5. Reconfiguring Packages

Sometimes you need to rerun a package’s configuration scripts—useful after restoring defaults or changing debconf answers:

sudo dpkg-reconfigure tzdata

This command re-executes maintainer scripts, prompting you to confirm or update settings as needed.

References

Future installments will cover advanced package building, repository management, and best practices for Debian package maintenance.

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