Unix Like Operating System has POSIX standard in common, which defines certain basic characteristics and these Operating Systems behave like UNIX.
Categories and Classification of Unix Like Operating System
System architectures of Unix Like Operating System has the advantages of a sophisticated design, security, stability and efficiency. Many Unix Like Operating System names ends with “-ux” or “-ix” or are recursive acronyms, UN*X or *nix. Unix Like Operating System have a general modularity, particularly in the separation of kernel and user account. Important components of a Unix Like Operating System is a Unix shell, especially the shell, its the free implementation of bash and the graphics are of server X11. Unix Like Operating System in general ranges from home user managementto client-server architecture mapping. They have the motto to use the system as everything is a file, which has led to a standardized directory structure, Filesystem Hierarchy Standard and daemon.
Generic Unix Like Operating System known as Unix derivatives, which includes most proprietary Unix variants (for example, AIX , IRIX and HP-UX ), BSD systems and OpenSolaris, for example, BSD-derived systems are FreeBSD or Darwin.
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Among branded Unix Like Operating System Mac OS X 10.5 and later is a BSD variant. Most of these systems are commercially sold and original Unix derivatives.
Functionally Unix Like Operating System behaves somewhat similar way as UNIX; good example is Linux.
System Architecture and License of Unix Like Operating System

GNU project developed a complete free operating system. Most commonly used License nowadays for Functional Unix Like Operating System is GNU variant which Linux kernel uses. Debian and some other organizations prefer the term GNU / Linux in order to appreciate the GNU project for the free software movement for any Unix Like Operating System.
Usage of Unix Like Operating System is mostly for a powerful workstation or a Server.
