I often have the problem of having to compare two ascii reports containing lots of numbers. The two reports contain almost the same values, but here and there small numerical/text differences may occur.
I'm interested in finding out where the differences are, and in the case of numerical differences, where the biggest difference is.
Until recently I just used a normal diff tool, but then it occurred to me that it should be easy to write what I call a "semantic diff" tool, i.e. a specialized diff tool that better highlights the kind of differences I'm interested in.
Here's an example of what I mean (the tables in real life are much biggger, and hopefully make more sense :) )