The Open Group is most famous as the certifying body for the UNIX trademark, and its publication of the Single UNIX Specification technical standard, which extends the POSIX standards and is the official definition of a UNIX system. If the official definition of a UNIX system is an extension of POSIX, then what exactly is POSIX?

I am looking for official documents on all POSIX standards and specifications. I would like to be able t read the docs to get a better understanding of UNIX systems and how they work at a low level...

What are the differences between POSIX, the Single UNIX Specification, and the Open Group Base Specifications? I think their purpose is for determining if an OS is Unix?

Nov 20, 2014 · @Sandburg POSIX is a standard, so it can't have built-ins. It doesn't define if something should be built into the interpreter or not, just what it has to do. These rules apply to both forms, test and [ alike. If a shell can do the evaluation on its own, that saves you a process and makes it somewhat faster, but the result has to be the same.

POSIX is a specification (written on papers, or in many web pages, notably OpenGroup). Unix is a family of operating systems, originally started at Bell Labs (by Thompson, Ritchie, Kernighan et al..).

Jan 2, 2013 · There is the well known while condition; do ...; done loop, but is there a do... while style loop that guarantees at least one execution of the block?

Dec 12, 2014 · POSIX is a family of operating system interface standards; you generally write code / run utilities in a conformant fashion when you want your application to run across a wide variety of Unix-ish systems.

Jan 28, 2017 · The HEREDOC embedded in the POSIX labelled version seems like a typo. Why would it make any sense to embed the here document in the function?

The LSB, POSIX, and the Single UNIX Specification all significantly involve userland. Simply using a kernel that is also used as the basis of a "unix-like", "mostly POSIX compliant" operating system -- GNU/Linux -- is not sufficient to make Android such as well. There are, however, some *nix-ish elements, such as the shell, which is a "largely compatible" Korn shell implementation …

Oct 19, 2016 · man 7 signal (Linux) or man 3 signal (BSD) will show you a complete table with a brief summary of the meaning of each signal: First the signals described in the original POSIX.1-1990 standard. Signal Value Action Comment ...