Good point about how to abort. Maybe it would be possible to short-circuit the fd somehow, so that the reader got an EOF, and that would in turn cause failure i

Good point about how to abort. Maybe it would be possible to short-circuit the fd somehow, so that the reader got an EOF, and that would in turn cause failure in the program reading the stream. At the same time, any success code from the program should be turned into an error exit code so the script could detect the failure. Not perfect, but arguably better than no failure at all.