On gusty, amd64
sudo dpkg -i --force-overwrite /var/cache/apt/archives/gimp_2.4.0~rc3-1ubuntu5_amd64.deb sudo apt-get upgrade
worked, thank you.
On gusty, amd64
sudo dpkg -i --force-overwrite /var/cache/ apt/archives/ gimp_2. 4.0~rc3- 1ubuntu5_ amd64.deb
sudo apt-get upgrade
worked, thank you.