> Posix shell is clunky has its limitations but there's nothing really flawed about it.

I think shellcheck is the best argument against this. POSIX shell is just stuffed to the brim with weird gotchas, places where the obvious way to write something causes subtle bugs down the line.

It's the only programming language I use that feels adversarial, where you have to be paranoid to properly solve simple tasks. (Admittedly some of that is because of the reliance on system programs rather than the shell language itself.)