# Bash Defensive Patterns

> 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.

Source: https://skillsagentes.com/skills/wshobson/agents/bash-defensive-patterns
Repository: https://github.com/wshobson/agents
Author: wshobson
License: MIT
Updated: hace 2 meses
Context cost: 47 tok installed, 498 tok once triggered, 2.9k tok with every bundled file
Bundle: 2 files, 11 KB
Permissions requested: none declared

## Install

```bash
npx -y skills add wshobson/agents --skill bash-defensive-patterns --agent claude-code
```

## What it does

- Aplica técnicas de programación defensiva en Bash: strict mode, comillas en variables, [[]], trampas de error
- Añade manejo de errores robusto, validación de entradas y limpieza segura de archivos temporales con mktemp/trap
- Incorpora logging estructurado, modo dry-run y diseño idempotente en los scripts
- Remite a `references/details.md` para patrones detallados y ejemplos trabajados

## Use it when

- Escribir scripts de automatización de producción
- Construir scripts de pipelines CI/CD
- Crear utilidades de administración de sistemas
- Desarrollar scripts que deben manejar casos límite de forma segura

## What triggers it

- "Ayúdame a escribir un script de Bash robusto para mi pipeline de CI/CD"
- "Necesito que este script de despliegue maneje errores correctamente"
- "Revisa mi script de administración de sistema para hacerlo más seguro"

## Files

- SKILL.md — 2 KB
- references/details.md — 10 KB

## SKILL.md

Reproduced verbatim from wshobson/agents under MIT. This section is the upstream document and is in English.

# 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

1. **Always use strict mode** - `set -Eeuo pipefail`
2. **Quote all variables** - `"$variable"` prevents word splitting
3. **Use [[]] conditionals** - More robust than [ ]
4. **Implement error trapping** - Catch and handle errors gracefully
5. **Validate all inputs** - Check file existence, permissions, formats
6. **Use functions for reusability** - Prefix with meaningful names
7. **Implement structured logging** - Include timestamps and levels
8. **Support dry-run mode** - Allow users to preview changes
9. **Handle temporary files safely** - Use mktemp, cleanup with trap
10. **Design for idempotency** - Scripts should be safe to rerun
11. **Document requirements** - List dependencies and minimum versions
12. **Test error paths** - Ensure error handling works correctly
13. **Use `command -v`** - Safer than `which` for checking executables
14. **Prefer printf over echo** - More predictable across systems

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Skills Agentes — https://skillsagentes.com/skills/wshobson/agents/bash-defensive-patterns