[sph]

No one really cares about the kernel internals, its origin or the license of it. What is prominent is the user-space components (i.e. shell and other binaries). macOS is closer to other BSDs than Linux is, as Linux usually ships with GNU libs and utilities.

[parkcedar]

You hardly notice the binaries though, especially since gnu cmd line utils are so similar anyway. You’d expect the c libs to be similar, but they’re not really (about as different as Mac to Linux anyway).

[sph]

GNU utils are not similar to BSD utils. My hardest time adjusting to macOS was learning that some command line options I was so used to didn't exist or didn't work the same way.

Sure, you have ls and df, but they behave similarly only on the surface.