# Shell

> Google's official Shell scripting style guide. Covers Bash scripting, naming conventions, error handling, portability, and shell best practices.

- Skill: `testdino-hq/shell` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add testdino-hq/shell`
- Raw SKILL.md: https://api.skillmd.com/api/skills/testdino-hq/shell/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: testdino-hq (https://skillmd.com/u/testdino-hq)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/testdino-hq/shell

---


# Google Shell Style Guide

> Official Google Shell scripting standards for consistent, maintainable Bash scripts.

## Quick Reference

### Golden Rules

1. **Use `#!/bin/bash`** — specify interpreter
2. **Quote variables** — `"$var"` not `$var`
3. **Check exit codes** — `set -e` or explicit checks
4. **Use functions** — organize code logically
5. **Avoid parsing `ls`** — use globs or find
6. **Use `[[` over `[`** — more features, fewer gotchas
7. **ShellCheck for linting** — catch common mistakes

### Naming Conventions (Preview)

| Element | Convention | Example |
|---|---|---|
| Functions | lowercase_with_underscores | `get_user_count` |
| Variables | lowercase_with_underscores | `user_count` |
| Constants | UPPER_SNAKE_CASE | `MAX_RETRIES` |
| Environment vars | UPPER_SNAKE_CASE | `PATH` |

### Basic Patterns (Preview)

```bash
#!/bin/bash
# ✓ CORRECT

set -euo pipefail  # Exit on error, undefined vars, pipe failures

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

function main() {
  local user_count="$1"
  
  if [[ -z "${user_count}" ]]; then
    echo "Error: user_count required" >&2
    return 1
  fi
  
  echo "Processing ${user_count} users"
}

main "$@"
```

## When to Use This Guide

- Writing new shell scripts
- Refactoring existing scripts
- Code reviews
- Setting up ShellCheck
- Onboarding new team members

## Install

```bash
npx skills add testdino-hq/google-styleguides-skills/shell
```

## Full Guide

See [shell.md](shell.md) for complete details, examples, and edge cases.