How to revert multiple git commits?

Question

I have a git repository that looks like this:

A <- B <- C <- D <- HEAD

I want the head of the branch to point to A, i.e. I want B

Answer 1

In my opinion a very easy and clean way could be:

go back to A

git checkout -f A

point master's head to the current state

git symbolic-ref HEAD refs/heads/master

save

git commit