The history and evolution of the Unix operating system is made available as a revision management repository, covering the period from its inception in 1970 as a 2.5 thousand line kernel and 26 commands, to 2017 as a widely-used 27 million line system. The 1.1GB repository contains about half a million commits and more than two thousand merges. The repository employs Git system for its storage and is hosted on GitHub. It has been created by synthesizing with custom software 24 snapshots of systems developed at Bell Labs, the University of California at Berkeley, and the 386BSD team, two legacy repositories, and the modern repository of the open source FreeBSD system. In total, about one thousand individual contributors are identified, the early ones through primary research. The data set can be used for empirical research in software engineering, information systems, and software archaeology. You can read more details about the contents, creation, and uses of this repository through this link.