Claude Code Bash Patterns

Claude Code Bash Patterns

Status: Production Ready ✅ | Last Verified: 2025-11-18

Quick Start

Basic Command

ls -la

Command Chaining

bun install && bun run build && bun test

Hooks

Create .claude-hook-pretooluse.sh:

#!/usr/bin/env bash
# PreToolUse hook - runs before every Bash command

echo "Running: $1"

Load `references/hooks-examples.md` for complete hook patterns.

The Five Core Patterns

1. Sequential Operations (&&)

Use when: Each command depends on previous success

git add . && git commit -m "message" && git push

Why: Stops chain if any command fails

2. Parallel Operations (Multiple tool calls)

Use when: Commands are independent

Message with multiple Bash tool calls in parallel

Load `references/cli-tool-integration.md` for parallel patterns.

3. Session Persistence

Use when: Need to maintain state across commands

# Set environment variable
export API_KEY="sk-..."

# Use in later commands (same session)
curl -H "Authorization: Bearer $API_KEY" api.example.com

4. Background Processes

Use when: Long-running tasks

npm run dev &
# Get PID with $!

5. Hooks for Automation

Use when: Need pre/post command logic

Load `references/hooks-examples.md` for all hook types.

Critical Rules

Always Do ✅

1. Use && for sequential dependencies (not semicolons)
2. Quote paths with spaces (cd "path with spaces")
3. Check environment before destructive ops (rm, git push --force)
4. Use specialized tools first (Read, Grep, Glob before Bash)
5. Set timeouts for long operations (up to 10 minutes)
6. Validate inputs before passing to shell commands
7. Use hooks for repeated patterns (logging, validation)
8. Maintain session state (export variables once)
9. Handle errors explicitly (check exit codes)
10. Document custom commands in .claude/commands/

Never Do ❌

1. Never use ; for dependent commands (use &&)
2. Never skip quoting paths with spaces
3. Never run rm -rf without confirmation
4. Never expose secrets in command output
5. Never ignore timeout limits (max 10 min)
6. Never use bash for file operations when specialized tools exist
7. Never chain with newlines (use && or ; explicitly)
8. Never force-push to main without explicit user request
9. Never skip hooks (--no-verify) without user request
10. Never use interactive commands (git rebase -i, git add -i)

Git Workflows

Basic Commit

git add . && git commit -m "feat: add feature"

Commit with Testing

npm test && git add . && git commit -m "fix: bug fix" && git push

Pull Request

git checkout -b feature/new && git add . && git commit -m "feat: new feature" && git push -u origin feature/new

Load `references/git-workflows.md` for complete workflows including:

• Feature branch workflow
• PR creation automation
• Commit message conventions
• Pre-commit validation

Hooks: Advanced Automation

PreToolUse Hook

`.claude-hook-pretooluse.sh`:

#!/usr/bin/env bash
COMMAND="$1"

# Log all commands
echo "[$(date)] Running: $COMMAND" >> ~/claude-commands.log

# Block dangerous patterns
if [[ "$COMMAND" =~ rm\ -rf\ / ]]; then
    echo "❌ Blocked dangerous command"
    exit 1
fi

Hook Types

• pretooluse - Before every Bash command
• stop - Before conversation ends
• user-prompt-submit - After user submits message

Load `references/hooks-examples.md` for all hook types and examples.

CLI Tool Integration

npm/bun

bun install && bun run build

wrangler (Cloudflare)

bunx wrangler deploy

gh (GitHub CLI)

gh pr create --title "Fix bug" --body "Description"

Load `references/cli-tool-integration.md` for complete tool patterns.

Custom Commands

Create .claude/commands/deploy.md:

---
description: Deploy to production
---

Run these steps:
1. Run tests: `npm test`
2. Build: `npm run build`
3. Deploy: `wrangler deploy`

User can invoke with: /deploy

Load `templates/custom-command-template.md` for template.

Security

Allowlisting Tools

`settings.json`:

{
  "dangerousCommandsAllowList": [
    "git push --force"
  ]
}

Secrets Management

# ✅ Good: Use environment variables
export API_KEY="$SECURE_VALUE"

# ❌ Bad: Hardcode secrets
curl -H "Authorization: Bearer sk-abc123..."

Load `references/security-best-practices.md` for complete security guide.

Common Use Cases

Use Case 1: Test Before Commit

npm test && git add . && git commit -m "message"

Use Case 2: Deploy with Validation

npm run lint && npm test && npm run build && bunx wrangler deploy

Use Case 3: Multi-Repo Operations

cd repo1 && git pull && cd ../repo2 && git pull

Use Case 4: Background Process

npm run dev &

Load `references/cli-tool-integration.md` for more patterns.

Troubleshooting

Issue: Command times out

Solution: Increase timeout or use background mode

# Background mode
npm run dev &

Issue: Path with spaces fails

Solution: Quote the path

cd "path with spaces/file.txt"

Issue: Hook blocks command

Solution: Check hook logic in .claude-hook-pretooluse.sh

Load `references/troubleshooting-guide.md` for all issues.

When to Load References

Load references/git-workflows.md when:

• Setting up git automation
• Creating PRs programmatically
• Need commit message conventions
• Want pre-commit validation patterns

Load references/hooks-examples.md when:

• Creating custom hooks
• Need hook templates
• Want validation patterns
• Implementing logging/security

Load references/cli-tool-integration.md when:

• Orchestrating multiple CLI tools
• Need tool-specific patterns
• Want parallel execution examples
• Troubleshooting tool integration

Load references/security-best-practices.md when:

• Configuring security guards
• Setting up allowlisting
• Managing secrets
• Preventing dangerous operations

Load references/troubleshooting-guide.md when:

• Debugging command failures
• Encountering timeouts
• Hooks behaving unexpectedly
• Session state issues

Using Bundled Resources

References (references/)

• git-workflows.md - Complete git automation patterns
• hooks-examples.md - All hook types with examples
• cli-tool-integration.md - Tool orchestration patterns
• security-best-practices.md - Security configuration guide
• troubleshooting-guide.md - Common issues and solutions

Templates (templates/)

• custom-command-template.md - Custom command template
• settings.json - Security settings example
• .envrc.example - Environment variables example
• github-workflow.yml - GitHub Actions integration
• dangerous-commands.json - Dangerous patterns list

Examples

Feature Development Workflow

git checkout -b feature/oauth && \
  npm test && \
  git add . && \
  git commit -m "feat(auth): add OAuth support" && \
  git push -u origin feature/oauth

CI/CD Pipeline

npm run lint && \
  npm test && \
  npm run build && \
  bunx wrangler deploy

Multi-Project Update

cd project1 && bun install && cd ../project2 && bun install

Official Documentation

• Claude Code Bash Tool: https://docs.claude.com/en/docs/claude-code/tools
• Hooks: https://docs.claude.com/en/docs/claude-code/hooks
• Custom Commands: https://docs.claude.com/en/docs/claude-code/custom-commands

Questions? Issues?

1. Check references/troubleshooting-guide.md for common issues
2. Review references/git-workflows.md for git patterns