Do you believe Linus wrote the operating system?

No, he did a great job with the kernel!

A significant amount of views about Linus creating the operating system - in the millions on encyclopedia.com alone... Additionally, users have asked questions on quora about Linus and writing cp. cp is part of coreutils, a GNU project. Using GNU Linux and informing users will reduce acceptance of this wrong information in posts like this one on Encyclopedia.com:

Overview. Software engineer Linus Torvalds is the creator of the Linux operating system, a program that by the late 1990s was getting attention as a potential competitor to the powerful Microsoft Windows, which runs about 85 percent of the world's computers.Operating systems: Linux, UnixBorn: 1970, Helsinki
Torvalds, Linus | Encyclopedia.com

The overview states creator of the Linux operating system.