How to undo a commit, push or merge - GhentAnalysis/heavyNeutrino GitHub Wiki
If you did a wrong commit, push or merge you can revert the branch to a given commit in the past using following commands:
git log # to show the list of commits, look here for the hash of the commit which has the code in the state you want to return to
git reset --hard <hash> # put in here the hash
git push origin --force # alternatively, use ghent instead of origin if you have to fix it in the GhentAnalysis fork
Alternatively, you can get the hash also from the github web-interface (right next to 'commit' when you click on a specific commit)