How to check real git diff before merging from remote branch?

Question

I want to check the real diff between remote branch and local branch. How can I do that?

Issuing the below command partially works, but it shows the diff of the new

Answer 1

What you want to do is, as suggested by Evgen Bodunov:

git diff ...remote/branch

This will diff changes from remote/branch and ignore changes from your current HEAD.