Hm, what commands are there that don't support filenames? `tr` is the only one I can think of, excluding ones that really can only operate on already-open file

Hm, what commands are there that don't support filenames? `tr` is the only one I can think of, excluding ones that really can only operate on already-open file descriptors (the `read` builtin, `flock` in certain modes, ...)