Long before the Linux desktop had a complete set of system tools, Debian and its derivatives had debconf [1], an all-purpose toolkit that the root user used to reconfigure an entire installation through the dpkg-reconfigure command. Today, many users have never heard of it, but dpkg-reconfigure remains a powerful tool in the hands of experts.

What makes dpkg-reconfigure so powerful is that it's not just a collection of settings to select. Instead, dpkg-reconfigure changes the settings of individual packages that are registered with debconf. These settings are determined by questions in a package's installation script [2]. Each question is given a priority, and when you choose an installer and its settings, you are choosing the priority of the questions you want to answer – anything from only the highest priority, in the case of the default Ubuntu installer, to the absolute lowest priority in an expert installation. The questions that you choose not to answer are given a default answer based on the information collected about your system and what should work on most systems.

After installation, dpkg-reconfigure gives you the chance to answer some or all of the questions again in the installation script. You can configure the package as precisely as you like, which makes dpkg-reconfigure ideal for troubleshooting or updating after installing hardware.

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