Unix Cli
Forty-four rules across eight categories for building CLI tools that play nice with pipes, shells, and other UNIX utilities. Critical stuff covers argument parsing, exit codes, and stream handling. Medium priority gets into signal handling and XDG config paths. Each rule links to a reference file with examples. The prioritization is helpful because you can ignore the incremental stuff when prototyping and come back later. Good for when you're writing a new tool from scratch or reviewing someone's CLI that doesn't quite feel right in a pipeline. The separation of stdout for data and stderr for diagnostics alone will save you debugging headaches.
- skills.sh installs
- 326
- GitHub stars
- 222
- last updated
- Aug 21, 2026
Install
$ npx -y skills add pproenca/dot-skills --skill unix-cli --agent claude-codeInstalls into .claude/skills of the current project.
Files
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 | MEDIUM-HIGH | help- |
| 7 | Signals & Robustness | MEDIUM | signal- |
| 8 | Configuration & Environment | MEDIUM | config- |
Quick Reference
1. Argument & Flag Design (CRITICAL)
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- Repository
- github.com/pproenca/dot-skills
- Categories
- Documentation, CLI & Terminal
- First seen
- Jun 3, 2026
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