name: shell-conventions description: Guides writing and updating bash scripts, CLI wrappers, and Node.js-based helper scripts. Use this when modifying scripts in the scripts/ folder, writing release utilities, or executing command-line processes. Do NOT use for standard Commander CLI commands inside src/commands/ or test files.

Shell Conventions and Coding Guidelines

Critical

• Portability and Strict Mode: All bash scripts must use #!/usr/bin/env bash as their shebang (never #!/bin/bash or #!/bin/sh) and immediately enable strict mode with set -euo pipefail.
• TypeScript ESM Imports: Any TypeScript scripts executed in the scripts context (such as tsdown compiled files) must use ESM imports with explicit .js extensions (e.g. import { x } from './x.js';).
• No Unsafe Evaluations: Avoid using eval or executing raw string interpolations in bash or Node's child_process.exec. Use safe argument arrays or library execution helpers like unrun where appropriate.

Instructions

1. Set Up the Script Environment:
   • Create the target shell script in the scripts/ directory.
   • Add the strict mode header:

     #!/usr/bin/env bash
     set -euo pipefail
     

   • Verify that the script has execute permissions (chmod +x scripts/filename.sh).
2. Resolve Paths Relativistically:
   • Determine the script directory relative to the project root to ensure robustness regardless of execution directory:

     SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
     PROJECT_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
     

   • Verify that all relative paths used in commands (e.g., pnpm run, vitest) are correctly absolute or relative to PROJECT_ROOT.
3. Handle Arguments and Flags Safely:
   • Use standard parameter expansion for default values to prevent "unbound variable" errors under set -u:

     ENV_TARGET="${1:-dev}"
     

   • Verify behavior by executing the script with and without arguments.
4. Implement Clean Up Traps:
   • Use shell trap definitions to clean up temporary files or background processes on exit:

     TMP_DIR=$(mktemp -d)
     cleanup() {
       rm -rf "$TMP_DIR"
     }
     trap cleanup EXIT
     

   • Verify cleanup by sending a SIGINT (Ctrl+C) or causing a deliberate command failure, ensuring the cleanup routine runs.

Examples

Example 1: Creating a test wrapper script

User says: "I want a script to run specific Vitest suites with coverage" Actions taken:

1. Create scripts/run-coverage.sh with the following contents:

   #!/usr/bin/env bash
   set -euo pipefail
   
   SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
   PROJECT_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
   
   cd "$PROJECT_ROOT"
   
   SUITE="${1:-scoring}"
   echo "Running Vitest coverage for suite: $SUITE"
   npx vitest run --coverage "tests/$SUITE"
   

2. Run chmod +x scripts/run-coverage.sh.
3. Verify execution by running ./scripts/run-coverage.sh scoring. Result: An executable, portable shell wrapper that follows strict execution principles.

Common Issues

• Error: "...: unbound variable":
  • Fix: You are accessing a parameter or environment variable that is not set. Provide a fallback default value using ${VAR:-default} or check if it is set first.
• Error: "No such file or directory" when referencing paths:
  • Fix: Ensure you are changing directory to the project root or utilizing an absolute script directory calculation (e.g. cd "$(dirname "${BASH_SOURCE[0]}")").
• Error: ESM Module resolution failure in TS script runner:
  • Fix: Check imports in scripts. In TypeScript scripts running under node, imports must contain explicit .js extensions, even when importing a .ts file.