Well, I almost managed to finish it, but the part with giving replaced file to another port turned out too hard for me..)
Nice one!
Still, as someone who just made a command line with history and autocompletion for my own project a couple of weeks ago, in a day or so, I must complain - it would be very nice to have at least history in such a game, especially if player is used to such a thing being present in a real CL (and I assume most of the players who played the game are)