Updated: 03/13/2021 by Computer Hope
Unix screen showing information about directories.

An operating system is said to be Unix-based or Unix-like if it's designed to function and behave similar to the Unix operating system. Examples of proprietary Unix-like operating systems include AIX (advanced interactive executive), HP-UX (Hewlett-Packard Unix), Solaris, and Tru64. Examples of open-source Unix-like operating systems are those based on the Linux kernel and BSD (Berkeley Software Distribution) derivatives, such as FreeBSD and OpenBSD.


All Unix-like operating systems support multiple users, strict segregation between kernel and user processes, preemptive multitasking, and a hierarchical file system. They often share the characteristic known as "everything is a file." Almost every system device and resource is abstracted as a stream of bytes that can be read and written like a regular file.

The GNU (GNU's Not Unix) toolchain is a collection of compilers, libraries, debuggers, and core utilities modeled on Unix. It's been ported to many Unix-like operating systems, and is used by default on GNU/Linux systems.

The Single Unix Specification and POSIX (portable operating system interface for Unix) standards help to establish a common set of commands and behaviors across Unix-like operating systems.

Unix-like operating systems

In addition to those listed above, Unix-like operating systems include:

Kernel, Operating System terms, Variant