On Mon, Jan 2, 2023 at 12:43 PM Larry McVoy <lm@mcvoy.com> wrote:

I was supporting a commercial product in the early 2000's and there
were all sorts of systems then that had old shells. Yes, you could make
everything a 2 level thing where the first level finds the correct shell,
but that's just fuss. Just make things portable, it's not that hard
and it works everywhere.

Making shell scripts portable means not using pipelines, because given "foo | bar", kshNN and zsh execute foo in a subshell and bar in the top-level shell, whereas in other shells, both foo and bar execute in subshells. (For this reason, Posix allows either behavior.) Not having pipelines is a pretty drastic limitation.