Today I’ve found this interesting software that allows you to literally undo any upgrade done adding a ppa (launchpad repository) and doing an apt-get update plus upgrade.
It’s name is PPA-PURGE!
The first thing to do is to install ppa-purge through apt-get:
sudo apt-get install ppa-purge
After that, you can undo any change of an installed repository (if you have removed a ppa, then re-add it) by entering:
sudo ppa-purge ppa:PPA_NAME
As an example, if you added the testing ppa for gimp 2.7.5 (https://launchpad.net/~matthaeus123/+archive/mrw-gimp-svn) and the other suggested and required repos, like:
…and that returned to you like a terrible self inflicted pain because (as an example) the gtk update broke your Unity UI and you are like:
Well.. ppa-purge could save your life (or mine) , just enter the command:
sudo ppa-purge ppa:matthaeus123/mrw-gimp-svn
and follow the on screen instructions.