Linus Decided To Follow The Design Of Unix

Because of the long history of Unix, the elegance of its basic design, the wide variety of software available for it, and his own familiarity with the system, Linus decided to write a version of Unix. Since the basic design was widely documented and used, he had plenty of information to work with.

The existence of the GNU Project helped out a great deal. This was (and is) a set of programs written for Unix-like operating systems that was freely available with source code. Once the operating system was even marginally functional, he had unitilities and applications available, both to test the system with and to make use of the system once tested. This was, of course, a tremendous help in gaining acceptance for Linux early on.