Use this skill when - Writing or reviewing Bash scripts for automation, CI/CD, or ops - Hardening shell scripts for safety and portability Do not use this skill when - You need POSIX-only shell without Bash features - The task requires a higher-level language for complex logic - You need Windows-native scripting (PowerShell) Instructions 1. Define script inputs, outputs, and failure modes. 2. Apply strict mode and safe argument parsing. 3. Implement core logic with defensive patterns. 4. Add tests and linting with Bats and ShellCheck. Safety - Treat input as untrusted; avoid eval and unsafe g…