This is an HIDAPI-based MagTek ID swipe software that works on OSX.
Most of the HID drivers for python/ruby/etc for these readers only work on linux, this uses the HIDAPI library that makes it compatiable with OSX also.
Enjoy!
I wrote this because I couldn't find anything like it avaliable for OSX.
It's a possibility that I'll write a full cocoa app later on.
For now, this is really simple, just run ./cardread