POSIXkompatible

POSIXkompatibel describes software, libraries, or operating systems that adhere to the POSIX standards, the Portable Operating System Interface maintained by IEEE. The goal of POSIX is to provide a portable, consistent interface for application programming and for command-line utilities, enabling greater portability of software across UNIX-like platforms.

The scope is divided mainly into POSIX.1, which defines the system APIs and library interfaces (such as open, read, write, fork, and exec), and POSIX.2, which covers the shell and utilities (for example, sh, ls, grep). Over time, the standards have evolved through versions such as POSIX.1-2001, POSIX.1-2008, and POSIX.1-2017, with various optional extensions. Real-world implementations vary in completeness; many systems provide full support for core POSIX features while offering additional non-POSIX extensions from environments like GNU or BSD.

Conformance is typically verified using test suites and, in some cases, official certification. The Open Group maintains UNIX certification programs, which are related but distinct from POSIX conformance; many Unix-like systems are POSIX-compliant without claiming UNIX certification. In practice, Linux with glibc or musl, macOS, and BSD variants aim for high POSIX compatibility, ensuring that portable software behaves consistently across platforms and that shell scripts and utilities operate predictably.

Limitations exist: POSIX specifies normative behavior only for supported features, and implementations may differ in edge cases, performance, or extensions. Some systems also implement non‑POSIX features, which can affect portability. Overall, POSIXkompatibel indicates a commitment to portable interfaces and predictable behavior across diverse environments.