Batch to detect if system is a 32-bit or 64-bit

Question

Does anybody know how to create a batch file that can shell one program if its a 64-bit system or shell another if its a 32-bit system?

Answer 1

On Linux, you can simply use "arch" at the command line.

ubuntu# arch
x86_64

On OSX (Snow Leopard), it returns "i386", even if you're on 64-bit hardware.