Can I ask which agent/model you used? I'm similarly irritated with shell script coding, but find I have to make scripts fairly often. My experience using various models but latterly Claude Code has been quite different -- it churned out pretty much what I was looking for. Also old, fwiw. I'm older than all shells.

It was Gemini, I picked the point of least resistance. I've heard Claude does better but haven't looked at it.