ever wanted to find the difference between two files – as in lines contained in one but not the other? probably not. but if you ever found yourself in such a situation you might find this little tool handy.
It will take two text input files, and give two outputs – one containing lines found in in1 but not in2, and vice-versa. It accepts drag-drop for files and should be quite performant (two lists of 10,000 lines takes around 100ms on a p4 3ghz). It should also scale quite well.
This was a 10-minute coding challenge.