bash-defensive-patterns
🎯SkillGuidance for writing safe, reliable Bash scripts, the small programs that automate tasks from the command line. It helps scripts catch errors, check inputs and run safely more than once.
Installation
npx skills add wshobson/agents --skill bash-defensive-patternsRun it in a terminal; it asks which AI coding tools to install it for (Claude Code, Codex, Cursor and more).
Uses skills.sh · Node.js 22.20+
After installing
Ask for related work and the agent uses it on its own, or call it yourself.
/bash-defensive-patternsInstall by hand
Copy the whole skill folder from GitHub to the place below. Copying only SKILL.md can leave out files the skill uses.
Open the skill folder →- This project
.claude/skills/bash-defensive-patterns/ - All projects
~/.claude/skills/bash-defensive-patterns/
These paths are for Claude Code. For other tools, the command above puts it in the right place.
What this skill does
Overview
This skill teaches safe ways to write Bash scripts. Bash scripts are small programs that run commands for you, such as deploying an app. The skill focuses on avoiding common mistakes that make scripts fail silently or cause damage.
Key Features
- Turn on strict mode with set -Eeuo pipefail so scripts stop when something goes wrong.
- Quote variables and check inputs to avoid surprising behavior.
- Clean up temporary files automatically, even when a script fails.
- Add a dry-run mode so you can preview changes before they happen.
- Write scripts that are safe to run again without breaking anything.
Who is this for?
It helps anyone who writes scripts for automation, build pipelines or server tasks. It is useful when a script must work every time and handle errors without surprises.
Summarized by AI from this skill's SKILL.md. Suggest a better one
SKILL.md
View on GitHub →Master defensive Bash programming techniques for production-grade scripts. Use when writing robust shell scripts, CI/CD pipelines, or system utilities requiring fault tolerance and safety.
Bash Defensive Patterns
Comprehensive guidance for writing production-ready Bash scripts using defensive programming techniques, error handling, and safety best practices to prevent common pitfalls and ensure reliability.
When to Use This Skill
- Writing production automation scripts
- Building CI/CD pipeline scripts
- Creating system administration utilities
- Developing error-resilient deployment automation
- Writing scripts that must handle edge cases safely
- Building maintainable shell script libraries
- Implementing comprehensive logging and monitoring
- Creating scripts that must work across different platforms
Detailed patterns and worked examples
Detailed pattern documentation lives in references/details.md. Read that file when the navigation tier above is insufficient.
Best Practices Summary
- Always use strict mode -
set -Eeuo pipefail - Quote all variables -
"$variable"prevents word splitting - Use [[]] conditionals - More robust than [ ]
- Implement error trapping - Catch and handle errors gracefully
- Validate all inputs - Check file existence, permissions, formats
- Use functions for reusability - Prefix with meaningful names
- Implement structured logging - Include timestamps and levels
- Support dry-run mode - Allow users to preview changes
- Handle temporary files safely - Use mktemp, cleanup with trap
- Design for idempotency - Scripts should be safe to rerun
- Document requirements - List dependencies and minimum versions
- Test error paths - Ensure error handling works correctly
- Use
command -v- Safer thanwhichfor checking executables - Prefer printf over echo - More predictable across systems
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