I have just enough time this morning to scratch out a brief note about icdiff. We went through a lot of diff variants over the summer, and for every one of those there was probably a colorizing tool that could pick up the visual slack.
That might be the strongest point for icdiff: that fact that you get most of the best features of conventional tools like diff proper, plus a healthy degree of control available in tertiary colorizing tools.
I have two screenshots there because it might be important to you to know that, by default, icdiff is going to abbreviate its output to show changed areas and their context. This took me a minute to figure out, since my original file had 52 lines or so, but icdiff kept showing a much shorter output.
The --whole-file flag is what controls that, and there are quite a few other options worth mention. icdiff has a built-in head feature that constrains the input to the first x lines of each file, which may be useful as opposed to piping both files through head before handing them to icdiff.
Another point that might interest you is the --highlight flag, which colorizes the background field instead of the character shape itself. The author suggests it’s ugly but fast; it caught my attention because it was much easier to spot single-character changes with this.
icdiff is in AUR, but I didn’t find it in Debian. Users of either distro (or others) should be able to get it working from its git repo though, so feel free to try it out.
icdiff is a decent tool with some good features and might be more accessible to casual users — like myself — as opposed to the classic diff or simpler attempts to colorize it. It’s rare that I need a diff tool but I can see where this one would come in handy.
Inconsolation 