9945-2009 - IEEE Information technology Portable Operating System Interface (POSIX) Base Specifications, Issue 7
Description: Revision and Adoption of IEEE Std 1003.1-2008, this standard defines a standard operating system interface and environment, including a command interpreter (or ‘‘shell’’), and common utility programs to support applications portability at the source code level. It is intended to be used by both application developers and system implementers.