No too sure of this is the way to do it but I think that MAC OS is UNIX based, and if so this is out of Maya 6 the complete ref.

save it as a .txt file then you change the permissions so out of the book

"open a shell then use the cd command to navigate to the location then type the following

chmod a=rwx filename.txt

(where filename is the name of the text file)

press enter (return) then to begin rendering type

./filename.txt

As I say I dont know if this is the correct way to do it for a mac but it might make more sense to a mac user as some of the commands might be commonplace in your OS vocab, and hence make sense.