Reconfigurando
Com o Debian e o Debian baseados (K / X / L / ubuntu) você pode usar o dpkg-reconfigure.
man dpkg-reconfigure:
NAME
dpkg-reconfigure - reconfigure an already installed package
SYNOPSIS
dpkg-reconfigure [options] packages
DESCRIPTION
dpkg-reconfigure reconfigures packages after they have already been
installed. Pass it the names of a package or packages to reconfigure.
It will ask configuration questions, much like when the package was first installed...
Isto é:
sudo dpkg-reconfigure kdm
ou
sudo dpkg-reconfigure gdm
ou ...
Kubuntu & LightDM
O LightDM é: link
Havia um plano: link
QLightDM: link
Com o Oneiric, a área de trabalho do Kubuntu está dependendo do KDM: link