What's the `POSIX 1003.2 standard'?
What's the `POSIX 1003.2 standard'?
POSIX is a name originally coined by Richard Stallman for a
family of open system standards based on UNIX. There are a
number of aspects of UNIX under consideration for
standardization, from the basic system services at the system
call and C library level to applications and tools to system
administration and management. Each area of standardization is
assigned to a working group in the 1003 series.
The POSIX Shell and Utilities standard has been developed by IEEE
Working Group 1003.2 (POSIX.2). It concentrates on the command
interpreter interface and utility programs commonly executed from
the command line or by other programs. An initial version of the
standard has been approved and published by the IEEE, and work is
currently underway to update it.
Bash is concerned with the aspects of the shell's behavior
defined by POSIX.2. The shell command language has of course
been standardized, including the basic flow control and program
execution constructs, I/O redirection and pipelining, argument
handling, variable expansion, and quoting.
The `special' builtins, which must be implemented as part of the
shell to provide the desired functionality, are specified as
being part of the shell; examples of these are `eval' and
`export'. Other utilities appear in the sections of POSIX.2 not
devoted to the shell which are commonly (and in some cases must
be) implemented as builtin commands, such as `read' and `test'.
POSIX.2 also specifies aspects of the shell's interactive
behavior as part of the UPE, including job control and command
line editing. Only vi-style line editing commands have been
standardized; emacs editing commands were left out due to
objections.
The Open Group has made an older version of its Single Unix
Specification (version 2), which is very similar to POSIX.2,
available on the web at
http://www.opengroup.org/onlinepubs/007908799/
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