POSIX

POSIX, a rewritten name that stands for "Portable Operating System Interface" in replacement for IEEE-IX for the IEEE Computer Society, is a set of standards for upkeeping compatibility across different operating systems as it defines system & user-levels APIs in the addition of utility interfaces and command line shells for portability with Unix, Unix-Based/Like operating systems, and more.

Modern Day POSIX Standards

There are many modern-day standards for POSIX, in order for a Unix-Based/Like operating system to POSIX-Compliant, it must provide implementations of the many POSIX APIs. These standards include the ability to use core services and/or processes properly: Core API Services and its processes, threads, signals, basic file I/O, as well as using Shell utilities such as bash and following commands like grep , sort, find, and plenty more.