$ git reset --hard HEAD (going back to HEAD)
$ git reset --hard HEAD^ (going back to the commit before HEAD)
$ git reset --hard HEAD~1 (equivalent to "^")
$ git reset --hard HEAD~2 (going back two commits before HEAD)
git reset --hard f414f31
git reset --soft HEAD@{1}
git commit -m "Reverting to the state of the project at f414f31"