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name: writing-shell-scripts description: >- Applies Bash style conventions when creating or editing shell scripts. Use when: (1) creating new shell scripts, (2) editing existing scripts in /bin/, or (3) reviewing Bash code for bugs or style issues.

Bash Style Guide

Apply the Bash conventions from ./references/BASH.md when creating or editing shell scripts.

Key Conventions

Read ./references/BASH.md for the complete guide. Summary:

Script Structure

• Shebang: #!/usr/bin/env bash
• Strict mode: set -euo pipefail
• Main function called at end: main "${@}"

Naming

• Functions: snake_case
• Local variables: lower_case
• Constants: ALL_CAPS with readonly

Syntax

• Variable expansion: ${var} not $var
• Command substitution: $(...) not backticks
• Tests: [[...]] not [...]
• Function syntax: function name() { } with both keyword and parentheses

Quoting

• Always quote variable expansions: "${var}"
• Always quote command substitutions: "$(cmd)"
• Use arrays for lists, not word splitting

Local Variables

• Declare with local
• Separate declaration from command substitution to preserve exit codes

Validation

Whenever possible, validate the script before finishing. Prefer using a project-specific validation script, if available. Common locations include declarations in package.json and scripts stored in bin/. If those aren't present, shellcheck is a commonly available linter for shell scripts.