How to list uninstalled but not purged packaged?

Question

I uninstalled tons of package with apt and always used remove.

Knowing I won't ever use them, and I worry about polluting my system with old config files, how can I purge all of them? The apt purge <package-name> command requires me to know what I want to purge, and I don't remember everything.

Answer 1

Simple way to do it is

dpkg -l | grep ^rc

This lists all (semi)installed packages, lines in list starts with state, rc means that the desired state is "remove" and the status is "conf-files".

If you want only package names:

dpkg -l | awk '/^rc/ {print $2}'