git rebasing and comparisons

git_rebase_and_differencing.md

Differencing a branch after a Rebase

Let’s say you have a branch. The copy on the server 'origin is up to date with your local branch.
You rebase to main: 

    git rebase main
        
(of course it would be best to do so if your local main is up to date with origin main)
Now, you want to know what changed - only for the working set of files in your branch - when you did the rebase. 
You can do this:

    git diff --stat origin/<branch_name> -- `git diff --name-only main`

What this says is “For all the files I changed with respect to main tell me which ones have changed after I did the rebase”.
And then if you have git difftool set up you can change that command to be:

    git difftool -y origin/<branch_name> -- `git diff --name-only main`
   
And that will use your differencing tool to show the diffs in each of those files.