> ssh does have some basic differentiation: "ssh exits with the exit status of the remote command or with 255 if an error occurred." Although, of course, 255 might be returned by a remote command (not sure how likely that is), so it's still ambiguous.

If one uses SSH for running such scripts, then it is not unlikely that the script itself would have another call to `ssh' to an even-more-remote machine.

And then there is the case of not expecting that a command would ever exit with 255 code. My trust to a system would be quite damaged if I happened to run into such a bug that a proper remote error would be mistaken for a network error. How can I, as the script writer, be sure that I never run into this situation?