You've been able to run Unix on Macs going back to the 1980s. In the 1990s there were several variations of Linux that ran on Macs, and Apple hired the mklinux guy to make sure that linux kernels ran ok on Macs.
The only time in the Mac's history that Apple wasn't working to make sure it could run Unix was 1984-1987ish before they released their flavor of Unix.
The only time in the Mac's history that Apple wasn't working to make sure it could run Unix was 1984-1987ish before they released their flavor of Unix.