For now I wrote a scarry while() loop with "parsing" done by
regular expressions and Term::ReadLine for prompt/editing/command history.
For example: if(/^l (\w+)/) implements command 'l' that accepts an argument (nevermind detail such as validating input for now).
I am sure that this is not the best way to implement input handling but I am stucked, and google/cpan gladly supply too many links to psh. Psh is neat, but I know enough perl to use
Term::Readline, and not quite enough to get ideas from much bigger programs. Melp!