Custom (interactive) shell with Python [closed]

Answer 1

The cmd module in the standard library could be a start -- if you have any trouble using it, please post more specific questions (ideally with some toy example showing what you're trying to achieve and what you're getting instead!).

Answer 2

You might have a look at pyparsing. It is definitely only about lexing and parsing, but that's definitely the hardest part of the problem.