Thanks ikegami and jbert. I don't get it, but will probably have to dig around for a tutorial on the web. Thanks. It sounds like you're saying that some files have a "secret decoder byte" (or bytes) at the very beginning of the file that say what the file's encoding is (i.e., ascii, iso-latin-1, UTF-8, Unicode). Maybe the editor doesn't show this byte (my guess is that it's something between 128 and 255 -- something an editor wouldn't draw on the screen anyway). But then, it would still be considered real data to various command line utils... Hmm...