Tue, we trace the evolution of the Unix code along the line that currently is FreeBSD over 50 years. The Linux kernel started its life decades later than Unix and it didn't (initially) share any code with the original Unix code base. Furthermore the GNU and other programs and tools required to form a GNU/Linux distribution have their own separate history, further complicating the picture. Linux's evolution, though shorter, is also interesting, but it is a very different story.