Use this just like the Unix program diff. It's smart enough to ignore differences in time triples (those numbers printed at the end of each event). It's not by any means perfect, but it works quite well when the files differ only in time triples. Usage: nqthmdiff file1 file2 To compile this, run your Ansii Standard C compiler (i.e., probably not the old-style compiler cc that comes with your Unix-based system) on the source file, e.g. gcc nqthmdiff.c -o nqthmdiff See also nqthmdiff.el, in the emacs subdirectory.