Oh, right, I missed that. I'm a source kind of person... :-) Speaking of using a pipe to an existing command, I originally mis-read the code to think there was only _one_ process involved, and that it was buffering its output into the pipe before doing the exec() itself - something like this: pipe(p); write_stuff(p[1]); close(0); dup(p[0]); close(p[0]); close(p[1]); execl("/bin/other", "other", arg, 0); Which is kind of a hack, but... it does avoid using a second process, although the amount of data that can be passed is limited. (IIRC, a pipe will hold at most 8 blocks, at least on V6.) Did this hack ever get used in anything?