- Using something like IPython, re.pl, or somesuch as a login shell, instead of bash/ksh/etc.
- Using initscripts, etc. written in Python or some other scripting language, and making no use of shell scripts whatsoever
- Not having any POSIX-compatible command shell installed
In other words I'm thinking of more a Windows-like approach, where the "CLI" is a REPL interface for a true scripting language (a la Powershell) that most programs are completely independent of.
Is this feasible? How reliant are Linux ports of desktop programs like Firefox, or web services like Apache, on having a working POSIX shell? How about the Linux kernel itself?