Writing Shell Scripts

Overview

Write shell code with an explicit portability target first, then apply strict quoting and a bounded ShellCheck remediation loop. Default to Bash readability and safety; switch to POSIX-only mode when the user asks for strict portability.

When to Use

• Creating or refactoring Bash scripts.
• Reviewing shell snippets for correctness and safety.
• Standardizing shebangs, quoting, variable expansion style, and test syntax.
• Deciding between POSIX-compliant syntax and Bash-specific features.
• Improving compatibility with zsh environments.

When NOT to use:

• The task is strictly fish, powershell, or Windows batch.
• The user explicitly wants pure POSIX sh and no Bash features (use POSIX mode from references/compatibility-matrix.md).