Emacs: ediff basics
Raw link: https://www.youtube.com/watch?v=pSvsAutseO0
In this ~15 minute video, I show how to inspect the differences between two or three files in a side-by-side comparison. Ediff lets you merge changes from one file to another while retaining all the text editing capabilities of Emacs (e.g. further edit the buffer and/or undo changes).