What are the differences between Linux Unix and Solaris?

Unix is a classification of operating systems that conform to a certain specification, based on that of the original Unix operating system created by AT&T. Systems certified as Unix can differ drastically, but must meet at least certain common elements.


Solaris is an implementation of Unix created by Sun Microsystems.

Linux is a family of operating systems based on a kernel written by Linus Torvalds. It shares some design goals and similarities with Unix, but has several advanced features and is not completely compatible with Unix. Legally, for a system to be described as "Unix", it must undergo a certification process. No Linux distribution has ever undergone this (very expensive) certification process to make it compliant with Unix standards.

Solaris uses older, POSIX-compliant utilities. Linux typically uses GNU utilities, which are generally compatible, but have different command switches and more features. This is beginning to change with the OpenSolaris project, which incorporates many GNU utilities.

Solaris and Linux both have features that the other lacks, and are not found in other Unix implementations either. These include DTRace and the ZFS file system (in Solaris) and dynamically loadable kernel modules and epoll (in Linux).