Hmm... why didn't I think of this rollover thingy.. I vaguelly remember actually doing something like that a long long time ago. Better then what I came up with so far. What I'm really hoping for of course is if someone can cut the file i/o down to less than sourcefilesize + outputfilesize.

I'm now wondering how the unix tail command works, those tools are usually quite golfed down. Anyone around fluent enough in C, with a unix distro handy and some time on their hands?

/me is of to do some Googling