It's neither, really. OS X takes its command line utilities from BSD world, while Linux's mostly come from GNU. They're independent implementations, and GNU utilities are as a rule much more featureful than their BSD equivalents. Or much more bloated, depending on your point of view.
Both aim to conform to the POSIX, but POSIX is a very spartan spec, people routinely use non-POSIX features without realizing it.
Both aim to conform to the POSIX, but POSIX is a very spartan spec, people routinely use non-POSIX features without realizing it.