POSIX.1-2008 is simultaneously IEEE Std 1003.1 -2008 and The Open Group Technical Standard Base Specifications, Issue 7. POSIX. 1-2008 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. POSIX. 1-2008 is intended to be used by both application developers and system implementors and comprises four major components (each in an associated volume): [1]General terms, concepts, and interfaces common to all volumes of this standard, including utility conventions and C-language header definitions, are included in the Base...

IEEE Std 1003.1-200x 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 applications developers and system implementors. IEEE Std 1003.1-200x comprises four major components (each in an associated volume): 1. General terms, concepts, and interfaces common to all volumes of IEEE Std 1003.1-200x, including utility conventions and C-language header definitions, are included in the Base Definitions volume of IEEE Std 1003.1-200x. 2. Definitions for system service functions and subrou...

The basic goal was to promote portability of application programs across UNIX system environments by developing a clear, consistent, and unambiguous standard for the interface specification of a portable operating system based on the UNIX system documentation. POSIX.1-2008 codifies the common,existing definition of the UNIX system.