bash-script-writing_skill

Overview

This skill teaches how to write clean, modular, production-ready bash scripts with strict error handling and a maintainable structure. It provides a recommended file layout, helper functions, naming conventions, and a checklist to ensure reliable automation. Use it to produce scripts that are readable, testable, and safe for production use.

How this skill works

The skill prescribes a template and conventions: strict mode (set -euo pipefail), a documented header, top-level main() orchestration, and small focused functions. It supplies logging helpers (log, info, warn, error), clear error patterns, and examples of good vs bad error handling. Follow the template to refactor or create scripts that fail fast with descriptive messages.

When to use it

• Creating a new automation script for deployment, backup, or maintenance
• Refactoring monolithic or fragile bash code into modular functions
• When asked to "write a script", "bash script", or "shell script" for automating tasks
• Adding robust error handling and clear logs to existing shell scripts
• Standardizing scripts across multiple machines for consistent behavior

Best practices

• Start every script with strict mode: set -euo pipefail
• Include a header with overview, usage, and configuration at the top
• Put main() near the top so the workflow is obvious
• Prefer small, single-purpose functions with verb-based names
• Use helper logging functions and always provide context in error messages
• Avoid silent failures; check command results and handle failures explicitly

Example use cases

• A deployment script that creates directories, uploads artifacts, and restarts services with clear failure messages
• A setup script that validates environment variables, configures hosts, and reports missing config
• Refactoring a large installer into parse_arguments, validate, install, and cleanup functions
• Daily maintenance cron script that logs progress and exits with meaningful codes
• Cross-machine sync tool that standardizes variables and error handling across systems