Just a guess on my part, but he may have meant "unix" and is using "Linux" incorrectly. Mac OS is a unix system. Linux has become so common that I have heard

Just a guess on my part, but he may have meant "unix" and is using "Linux" incorrectly. Mac OS is a unix system. Linux has become so common that I have heard many people say Linux when they mean the more general term unix. Let's assume the best instead of the worst.