Unix-like Operating Systems
A UNIX-LIKE system is an OPERATING-SYSTEM that behaves in a manner similar to the original UNIX developed at BELL-LABS. These systems are characterized by their multi-user and multi-tasking capabilities, often adhering to the POSIX standards to ensure software compatibility across different platforms. The design philosophy emphasizes small, modular tools that can be combined via PIPES to perform complex tasks.
Major branches of the UNIX-LIKE family include LINUX, which utilizes the LINUX-KERNEL created by LINUS-TORVALDS, and the BSD family, which originated at the UNIVERSITY-OF-CALIFORNIA-BERKELEY. While MACOS by APPLE is fully certified as UNIX, it is frequently grouped with UNIX-LIKE systems due to its DARWIN base and OPEN-SOURCE components.
For technical specifications, see The POSIX Standard and the Linux Kernel Archives.