Thanks for the pointer to lish! I didn't know it had all that, I know it exists but was intimated by its non-standard packaging...

I decided to not go too far on the structured/object shell route for Unix in Lisp, instead trying to get existing Unix utilities to work as seamlessly as possible first. But maybe in the future I could integrate some work from lish. That's lots of impressive work under yew/los and yew/tools!