I don't know why shelljs hasn't found me earlier :(

This is bash the way I would feel comfortable with it, JavaScript style.

[Update 2014-02-11] well it's not really all bash can do, it just imitates the interface using JS as the language. I was looking for the REPL. Well start > node and there is the REPL :). So I played with it. Not as powerful and far from a replacement for bash but it spins quite some ideas.