How to automate cleanup of config files from past pkgs as reported by "dpkg -l | grep ^rc"

Question

There are a number of pkgs that weren't removed with "apt-get purge" and I would like to automate cleaning them up.

You can't apt-get purge apache2.2-common because the pkg is already removed.

You can still list the files that are in the pkg with dpkg -L apache2.2-common.

This means I could just remove the list of files in the pkg, but how would dpkg know this? How do I remove the config files left behind AND remove it from the following report?

Example output:

$ dpkg -l | grep ^rc
rc  apache2.2-common                  2.2.14-5ubuntu8.10                Apache HTTP Server common files
rc  libapache2-mod-php5filter         5.3.10-1ubuntu2ppa6~lucid         server-side, HTML-embedded scripting languag
rc  libapr1                           1.3.8-1ubuntu0.3                  The Apache Portable Runtime Library
rc  libaprutil1                       1.3.9+dfsg-3ubuntu0.10.04.1       The Apache Portable Runtime Utility Library
rc  libgd2-xpm                        2.0.36~rc1~dfsg-3.1ubuntu1        GD Graphics Library version 2
rc  libt1-5                           5.1.2-3ubuntu0.10.04.2            Type 1 font rasterizer library - runtime
rc  php5-gd                           5.3.10-1ubuntu2ppa6~lucid         GD module for php5
rc  ssl-cert                          1.0.23ubuntu2                     simple debconf wrapper for OpenSSL

Answer 1

Something like this will find the package names:

dpkg --list | grep ^rc | awk '{print $2}'

Or to remove the number of pipes you can use this:

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

So the next step is to feed one of those lists into dpkg --purge. Using a subshell you can do that easily:

dpkg --purge $(dpkg --list | grep ^rc | awk '{print $2}')

Simple!