http://www.soft32.com/download_13987.html
But I don't think it runs on a Mac. Maybe you can find a Windows PC to do it?

Of course, you could also try to use sed (streaming editor). Originally, it's Unix-based (so no problem in Linux), but I've used a Windows clone once. And there might very well be a Mac version, given that current Macs are Unix-based in essence.

Kees