To remove a package along with its configuration files using dpkg, which flag is required?

The removal of a package along with its configuration files in Debian-based systems like Ubuntu requires the use of the --purge flag or its shorthand, -P, with the dpkg command.

When using dpkg with the --purge flag, both the package and its configuration files are removed from the system. This is useful for ensuring that no remnants of the package remain, especially if it is to be reinstalled later, and you want a clean slate. In contrast, other options may not adequately remove configuration files, which may lead to issues if you decide to reinstall the package in the future.

In summary, the -P option specifically serves the purpose of purging a package along with its configuration files, making it the correct choice for this operation.