Mac OS is not linux. Mac OS runs a Mach) kernel, while the Linux kernel is something totally different (simplified version: they run programs in different "levels", and with different paradigms). The kernel interfaces with your computer's hardware, and is therefore called upon when you execute a program to translate the program's instructions to something your computer can understand. When people talk about "linux", they are generally speaking of the linux kernel, plus all of the programs that run on top of it. These programs must be compiled specifically for the kernel and associated other programs that make up your operating system. Sometimes people refer to Mac OS as being Unix based. This is true, but it does not extend to allowing binary compatibility between all Unix operating systems. You wouldn't think that you can take Ford engine parts and put them in a Ferrari as-is. Even programs compiled under a different compiler version (GCC for C) may refuse to run on the same operating system, if the OS version is significantly older or newer.