Claude Code Quickstart

Installation

NPM Installation

Requirements: Node.js 18+

npm install -g @anthropic-ai/claude-code

Native Installer (Beta)

Homebrew (macOS):

brew install --cask claude-code

macOS/Linux/WSL:

curl -fsSL https://claude.ai/install.sh | bash

Windows PowerShell:

irm https://claude.ai/install.ps1 | iex

Verify Installation

claude --version

Authentication

First Login

Start an interactive session and authenticate:

claude
/login

Authentication Options

Claude.ai (Recommended):

• Subscription-based
• Easiest setup
• Best for individual developers

Claude Console:

• API access with prepaid credits
• Good for teams and enterprises
• Requires API key setup

Note: Credentials are stored securely and you won't need to log in again unless you explicitly log out.

Basic Workflow

1. Start a Session

Navigate to your project directory:

cd /path/to/your/project
claude

2. Explore Your Codebase

Ask natural language questions:

"what does this project do?"
"where is the main entry point?"
"how does authentication work?"
"show me the API endpoints"

3. Make Code Changes

Request modifications:

"add a new function to validate email addresses"
"refactor the user controller for better error handling"
"add unit tests for the authentication module"

Approval process:

• Claude requests approval before modifying files
• Review changes in the diff viewer
• Approve individually or enable "Accept all" mode

4. Git Operations

Use conversational prompts:

"what files have I changed?"
"commit my changes with a descriptive message"
"create a pull request for this feature"

Essential Commands

Interactive Mode

Command	Purpose
claude	Start interactive mode
claude "task"	Run single task then exit
/help	Show available commands
/clear	Clear conversation history
/memory	Edit CLAUDE.md memory files
/permissions	Configure tool permissions
/model	Select AI model

Keyboard Shortcuts

Shortcut	Action
Ctrl+C	Cancel current operation
Ctrl+D	Exit Claude Code
Ctrl+L	Clear screen (keeps history)
Esc Esc	Rewind code/conversation
↑/↓	Navigate command history
Tab	Toggle extended thinking
?	Show help

Common First Tasks

Understand a Project

"Explain the project structure"
"What technologies are used here?"
"Where should I start if I want to add a new feature?"

Fix Issues

"Find and fix any TypeScript errors"
"Resolve linting issues"
"Fix the failing tests"

Add Features

"Add input validation to the signup form"
"Create a new API endpoint for user profile updates"
"Implement pagination for the product list"

Improve Code

"Refactor this component for better readability"
"Add error handling to all API calls"
"Improve test coverage"

Pro Tips

Be Specific

❌ Vague:

"make this better"
"fix the code"

✅ Specific:

"refactor this function to reduce complexity"
"fix the null pointer exception in getUserProfile"
"add JSDoc comments to all exported functions"

Break Down Complex Tasks

Instead of:

"Build a complete user management system"

Try:

1. "Create a user model with validation"
2. "Add CRUD endpoints for users"
3. "Implement authentication middleware"
4. "Add unit tests for user operations"

Use Context Efficiently

Attach relevant files:

"Review @src/utils/validation.ts for security issues"

Reference specific code:

"Optimize the database query in getUsersByRole function"

Manage Permissions

Start cautious, then adjust:

1. Begin with manual approval mode
2. Review Claude's changes carefully
3. Enable auto-accept for trusted operations
4. Configure specific permissions via /permissions

Next Steps

Learn More Features

1. Custom Commands: Create slash commands for frequent tasks
2. Memory Files: Set up CLAUDE.md for project guidelines
3. Subagents: Configure specialized agents for specific tasks
4. Hooks: Automate workflows with event-driven scripts
5. Plugins: Install marketplace plugins for extended functionality

Configure Your Workflow

Create .claude/CLAUDE.md:

# Project Guidelines

## Code Style
- Use TypeScript strict mode
- Prefer functional components
- Follow existing naming conventions

## Testing
- Write tests for all new features
- Maintain >80% coverage

## Git
- Use conventional commits
- Squash before merging

Set up permissions in .claude/settings.json:

{
  "permissions": {
    "allow": [
      "Bash(npm run *)",
      "Bash(git status:*)"
    ],
    "deny": [
      "Read(.env*)",
      "Bash(rm:*)"
    ]
  }
}

Explore Advanced Features

Headless mode for automation:

claude -p "run tests and fix failures" \
  --allowedTools "Bash,Read,Edit,Write" \
  --output-format json

Session management:

# Continue previous session
claude --continue "add more tests"

# Resume specific session
claude --resume <session-id> "finish the refactoring"

Custom models:

claude --model opus  # For complex reasoning
claude --model haiku # For quick tasks

Common Patterns

Daily Development

# Start your day
cd project
claude

# Review changes
"what did I change yesterday?"

# Continue work
"finish implementing the user profile feature"

# Commit
"commit my changes with a good message"

Code Review

# Review PR
git diff main | claude -p "review these changes for issues"

# Address feedback
claude
"fix the security issue in the authentication handler"

Bug Fixing

# Start with error
claude "fix: TypeError: Cannot read property 'name' of undefined in dashboard"

# Debug
"show me where this error occurs"
"explain why this is happening"
"fix it and add tests to prevent regression"

Troubleshooting

Command Not Found

# Verify installation
npm list -g @anthropic-ai/claude-code

# Check PATH
echo $PATH | grep npm

# Reinstall if needed
npm install -g @anthropic-ai/claude-code

Authentication Issues

# Log out and back in
claude
/logout
/login

# Or reset auth
rm -rf ~/.config/claude-code/auth.json
claude
/login

Performance Issues

# Clear conversation
/clear

# Compact context
/compact

# Use more specific queries

Getting Help

Within Claude Code:

/help           # Show all commands
/bug            # Report an issue
/doctor         # Check installation

External Resources:

• Documentation: https://docs.claude.com/en/docs/claude-code
• GitHub: https://github.com/anthropics/claude-code
• Issues: https://github.com/anthropics/claude-code/issues

Summary

Installation: ~30 seconds

npm install -g @anthropic-ai/claude-code
claude
/login

First task: Ask about your project

"what does this project do?"

Make changes: Be specific

"add input validation to the signup form"

Commit: Use natural language

"commit my changes"

That's it! You're ready to use Claude Code for development.