POSIX is an acronym for "Portable Operating System Interface", a family of standards specified by the IEEE for maintaining compatibility between operating systems.
POSIX is a family of standards that specifies the behaviour of Unix-like operating systems.
These standards define:
- A standard operating system interface and environment.
- A programming API for the C programming language.
- The behavior of a command interpreter (or “shell”).
- The behavior of common utility programs invocable from the shell.
The current set of POSIX standards is available online.