Unix Like

Used to describe OperatingSystems which are similar to the UnixOperatingSystem. Examples: GnuLinux; various BsdOss (e.g. FreeBsd, OpenBsd, NetBsd); MacOsx.

What is Unix?

The "Single Unix Spec" can be found at http://www.opennc.org/onlinepubs/7908799/index.html

TheOpenGroup? holds the trademark for Unix and are the creators of this specification.

For a product to be called Unix, it must go through conformance testing. It is an expensive process and the various Linux products seem satisfied to be termed UnixLike.

There is a movement under way to bring a degree of uniformity to the LinuxDistribution called the LinuxStandardBase. A distribution may be called "Linux" without conforming to this specification.

Back in the 1980s, there was a debate over whether BSD or AT&T constituted the real Unix. I'm thinking that FreeBSD (a direct decendent of 386BSD, which came straight from the original CalBerkeley BSD) and cousins have more right to be called the definitive Unix than some little-known product from SCO which to my knowledge doesn't actually have any of the original Unix code in it and can only be called the "real" Unix because they bought and control the Unix trademark.

Given current market shares, it may be more accurate to say that UNIX(TM) is a LinuxLike? operating system. SunMicrosystems CEO ScottMcNealy actually said: "All Linux applications run on Solaris, which is our implementation of Linux." (http://www.zdnet.com/eweek/stories/general/0,11011,2662720,00.html)