Shell without a userland is like FORTH without the ability to define new words. It's really contrary to the whole idea of what a shell is. Bootstrapping in very constrained conditions makes some sense, but where would you have a POSIX shell and not a POSIX userland (or close equivalent) to work with? When I wrote a similar compiler in shell, I purposely offloaded everything I could to external tools and used the shell for composition, so I found the approach intriguing and wanted to ask. I wasn't trying to criticize or dismiss the project, I think it's really cool or else I wouldn't have bothered to read the code in the first place.