I'm working on a branch where I have changed file A in several commits and now I want to revert all changes from it so that file A's state is same as initial state it had when I had first created the branch. What is the easiest way to achieve this?
git checkout <sha1_of_commit> file/to/restore
It will revert file to state after <sha1_of_commit> commit.
If you want to revert it to state before this commit use
git checkout <sha1_of_commit>~1 file/to/restore