There was a lot of Unix already, and Linux ate it's lunch by being a simple recompile away.

MacOS does a lot to try and hide that it's a Unix.

> There is a ton of cross pollination between mac and Linux software

Do we have any good examples, because Apple spends a lot of effort breaking cross platform compatibility?

> at least on the command line.

There is a lot of Linux command line software ported to MacOS, but I can't think of any good examples for the other way around.