unix-cli

name

unix-cli

description

UNIX command-line interface guidelines for building tools that follow POSIX conventions, proper exit codes, stream handling, and the UNIX philosophy. This skill should be used when writing, reviewing, or designing CLI tools to ensure they integrate properly with the UNIX tool chain. Triggers on tasks involving CLI tools, command-line arguments, exit codes, stdout/stderr, signals, or shell scripts.

UNIX/POSIX Standards CLI Best Practices

Comprehensive guidelines for building command-line tools that follow UNIX conventions, designed for AI agents and LLMs. Contains 44 rules across 8 categories, prioritized by impact from critical (argument handling, exit codes, output streams) to incremental (configuration and environment).

When to Apply

Reference these guidelines when:

• Writing new CLI tools in any language
• Parsing command-line arguments and flags
• Deciding what goes to stdout vs stderr
• Choosing appropriate exit codes
• Handling signals like SIGINT and SIGTERM

Rule Categories by Priority

Priority	Category	Impact	Prefix
1	Argument & Flag Design	CRITICAL	args-
2	Exit Codes	CRITICAL	exit-
3	Output Streams	CRITICAL	output-
4	Error Handling	HIGH	error-
5	I/O & Composition	HIGH	io-
6	Help & Documentation