What exactly is POSIX? - Unix Linux Stack Exchange POSIX first was a standard in 1988 long before the Single UNIX Specification It was one of the attempts at unifying all the various UNIX forks and UNIX-like systems POSIX is an IEEE Standard, but as the IEEE does not own the UNIX® trademark, the standard is not UNIX® though it is based on the existing UNIX API at that time
Where can I find official POSIX and UNIX documentation? In addition to the web links, you can also install the POSIX man pages, e g on a Debian-like system they are available as manpages-posix-dev package Then you can lookup the POSIX version of say - the read system call - via: $ man 3p read Or the mv command $ man 1p mv Just add a p to the usual man page section number
posix - Is test or [ or [[ more portable both between bash shells and . . . @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
linux - How do executables use POSIX to keep compatibility between . . . Note that POSIX specifies a c99 utility and how to use it to get an executable that can make use of the POSIX interface See also the It is unspecified whether the libraries libc a, libl a, libm a, libpthread a, librt a, libtrace a, libxnet a, or liby a exist as regular files
Difference between POSIX, Single UNIX Specification, and Open Group . . . Today, POSIX and SUS are basically the same thing; SUS encompasses a little more Quoting here: Beginning in 1998, a joint working group known as the Austin Group began to develop the combined standard that would be known as the Single UNIX Specification Version 3 and as POSIX:2001 (formally: IEEE Std 1003 1-2001) It was released on January 30
List of shells that support `local` keyword for defining local . . . I know that Bash and Zsh support local variables, but there are systems only have POSIX-compatible shells And local is undefined in POSIX shells So I want to ask which shells support local keyword for defining local variables? Edit: About shells I mean the default bin sh shell
What does in the POSIX locale mean? - Unix Linux Stack Exchange POSIX does define base requirements for some character classes (“automatically included characters”); for example, a locale’s definition of “upper” should include characters A to Z from the POSIX definition But POSIX is careful to not even require that; extensions are allowed to prevent the automatic inclusion –
What is POSIXLY_CORRECT and what makes it change (Centos 8. 4)? The POSIXLY_CORRECT environment variable is a variable that helps utilities select behavior when the tool implements a behavior that differs from what the POSIX standard prescribes The bash shell will act slightly differently in POSIX mode (i e if set -o posix is enabled, or the shell is started as sh)
c - Get output of `posix_spawn` - Unix Linux Stack Exchange The third parameter of posix_spwan is a pointer of type posix_spawn_file_actions_t (one you have given as NULL) posix_spawn will open, close or duplicate file descriptors inherited from the calling process as specified by the posix_spawn_file_actions_t object