Enter the git diff command in the following format:
git diff main..second-branch [[Enter]]
Type git diff, followed by the name of your first branch, two dots, and the second branch. The resulting output is a comparison of the two branches.

GitHub

github.com

While you can't compare two branches directly on GitHub, you can use the git diff command via your terminal or shell to view a detailed comparison of the two branches. Let's explore how to do it in a few easy steps.

How to Compare Branches in GitHub