
It is not fashionable nowadays to speak of the merits of the command line, in an age where things like streaming video and Aqua are an integral part of our daily life. However, I do not think that typed-in commands must necessarily be consigned to the dustbin of computer history. Of course, I am not suggesting that we all drop X and Windows and pretend like we are living in the early eighties. The command line interface still has much to offer us, and many of its benefits simply cannot physically be emulated or even replaced by graphical ones.
I'm not sure about Ruby, but there is a command line shell that uses Python which is kind of similar and surprisingly powerful: iPython at http://ipython.scipy.org/.
With this, a user can enter the normal shell commands (bash commands I believe), but it also acts as a Python interpreter so you have a scripting language that is more powerful than bash's.