Print Diff of two text files
I thought perhaps BBEdit might have what you want. Under the Search menu, there is a Find Differences command, wherein the text files can be selected.

However, the result shows the file contents side-by-side, on screen. When printed, the output is merely a list of which lines did not match.

As a workaround, might I suggest the following:


Perform the comparison using whatever software works for you.
Get a screen capture (i.e., bitmap) of each page of side-by-side text.
Print the bitmaps.


It will be somewhat rough, but you'll (probably) have the printed sheets of line comparisons that you need.