shell

name	shell
description	Shell scripting best practices for writing safe, portable, and maintainable bash/sh scripts. Use when writing, reviewing, or refactoring shell scripts, Dockerfile RUN commands, Makefile recipes, CI pipeline scripts, cron jobs, or systemd ExecStart directives. Triggers on bash, sh, POSIX, ShellCheck, error handling, quoting, variables, set -euo pipefail.

Shell Scripts Best Practices (Community)

Comprehensive best practices guide for shell scripting, designed for AI agents and LLMs. Contains 49 rules across 9 categories, prioritized by impact from critical (safety, portability) to incremental (style). Each rule includes detailed explanations, real-world examples comparing incorrect vs. correct implementations, and specific impact metrics.

When to Apply

Reference these guidelines when:

• Writing new bash or POSIX shell scripts
• Reviewing shell scripts for security vulnerabilities
• Debugging scripts that fail silently or behave unexpectedly
• Porting scripts between Linux, macOS, and containers
• Optimizing shell script performance
• Setting up CI/CD pipelines with shell scripts

Rule Categories by Priority

Priority	Category	Impact	Prefix	Rules
1	Safety & Security	CRITICAL	safety-	6
2	Portability	CRITICAL	port-	5
3	Error Handling	HIGH	err-	8
4	Variables & Data	HIGH	var-