Command Line Interface

POSIX Utility Conventions

The POSIX Utility Conventions specify the expected behavior of command line utilities including argument parsing, flag styles, end-of-options separators, and exit status. Following POSIX makes a tool feel native to UNIX-like environments and predictable when composed in pipelines and shell scripts.

Documentation GitHub

Other Resources

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Specification

https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap12.html

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Reference

https://www.gnu.org/software/libc/manual/html_node/Argument-Syntax.html

API entry from apis.yml

aid: command-line-interface:posix-utility-conventions
name: POSIX Utility Conventions
description: The POSIX Utility Conventions specify the expected behavior of command line utilities including
  argument parsing, flag styles, end-of-options separators, and exit status. Following POSIX makes a tool
  feel native to UNIX-like environments and predictable when composed in pipelines and shell scripts.
humanURL: https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap12.html
baseURL: https://pubs.opengroup.org
tags:
- Conventions
- POSIX
- Standards
- UNIX
properties:
- type: Specification
  url: https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap12.html
- type: Reference
  url: https://www.gnu.org/software/libc/manual/html_node/Argument-Syntax.html
x-features:
- Defines short flags, long flags, and option arguments
- Specifies the `--` end-of-options sentinel
- Standardizes exit status conventions
- Foundation for getopt and getopts utilities
x-useCases:
- Writing portable CLI utilities for UNIX-like systems
- Implementing argument parsers that match user expectations
- Documenting tool behavior in man pages