I have moved some code from a file to another file, and applied little changes in it. I would like to have a diff to see those changes.

The problem seems pretty common to me, but I have never needed to do such a thing. I only know how to compare the same file with himself in a previous revision, or 2 different files in the same revision.

Are there `git diff` options to compare one file in the current revision to another file in another commit? Or any other way?