Getting Started with Claude Code

Claude Code is Anthropic's official terminal-based AI coding assistant. If you live in the terminal, this is your tool.

Why Claude Code?

Claude Code excels when you:

• Prefer terminal over GUI
• Work with complex, multi-step tasks
• Need agentic capabilities (autonomous work)
• Want deep git integration
• Require MCP (Model Context Protocol) connections

Installation

Prerequisites

• Node.js 18+ installed
• npm or yarn
• Anthropic API key

Install Globally

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

Verify Installation

claude --version
# Output: claude <version number>

First-Time Setup

Set your API key via environment variable:

export ANTHROPIC_API_KEY=your-key-here

Or add it to your shell profile (~/.zshrc or ~/.bashrc) to persist across sessions.

Basic Usage

Start an Interactive Session

cd your-project
claude

This opens an interactive REPL where you can chat with Claude about your code.

Single Command

claude "Explain what this project does"

With File Context

claude "Review this file for security issues" --file src/auth.ts

The Interface

┌─────────────────────────────────────────────────────────────┐
│ Claude Code                                                 │
│ Working directory: ~/projects/my-app                        │
│ Model: claude-sonnet-4-6                                    │
├─────────────────────────────────────────────────────────────┤
│                                                             │
│ You: Create a utility function for date formatting          │
│                                                             │
│ Claude: I'll create a date formatting utility for you.      │
│                                                             │
│ [Creating file: src/utils/dateFormat.ts]                    │
│                                                             │
│ ```typescript                                               │
│ export function formatDate(date: Date): string {            │
│   return date.toLocaleDateString('en-US', {                 │
│     year: 'numeric',                                        │
│     month: 'long',                                          │
│     day: 'numeric'                                          │
│   });                                                       │
│ }                                                           │
│ ```                                                         │
│                                                             │
│ [Apply changes? (y/n)]                                      │
│                                                             │
├─────────────────────────────────────────────────────────────┤
│ > _                                                         │
└─────────────────────────────────────────────────────────────┘

Essential Commands

Slash Commands

Command	Description
/help	Show available commands
/clear	Clear conversation history
/model	Change AI model
/config	View/edit configuration
/review	Review a pull request
/memory	View and manage memory files
/cost	Show API usage cost

Keyboard Shortcuts

Key	Action
Ctrl+C	Cancel current operation
Ctrl+D	Exit Claude Code
Up/Down	Navigate history
Tab	Autocomplete file names

Configuration

Project-Level Configuration

Create a CLAUDE.md file in your project root to give Claude persistent instructions:

# Project Rules

- Use TypeScript for all new files
- Follow the existing code style
- Include JSDoc comments for public functions
- Run tests before committing

Settings File

Create .claude/settings.json in your project for tool permissions and settings:

{
  "permissions": {
    "allow": [
      "Bash(git *)",
      "Bash(npm *)",
      "Read",
      "Write",
      "Edit"
    ]
  }
}

Your First Task

Let's complete a real task:

Step 1: Navigate to Project

cd ~/my-project

Step 2: Start Claude Code

claude

Step 3: Ask Claude

Create a simple API endpoint that returns the server health status.
Include timestamp and memory usage.

Step 4: Review Changes

Claude will show you the proposed changes with diffs.

Step 5: Apply or Modify

• Type y to apply all changes
• Type n to reject
• Type e to edit before applying

IDE Integration

VS Code Extension

1. Install "Claude Code" from VS Code marketplace
2. Press ⌘/Ctrl + Shift + P
3. Type "Claude Code: Open Terminal"
4. Claude Code runs in integrated terminal

JetBrains Integration

1. Install "Claude Code" plugin
2. Open Terminal panel
3. Run claude command

Comparison with Cursor

Feature	Claude Code	Cursor
Interface	Terminal	GUI
Best for	Complex tasks, automation	Visual editing
Learning curve	Higher	Lower
Customization	Extensive	Moderate
Memory (CLAUDE.md)	Built-in	Manual
MCP Support	Native	Limited

Use Both: Many developers use Cursor for daily coding and Claude Code for complex refactoring or automation tasks.

Troubleshooting

Command Not Found

# Ensure global npm bin is in PATH
export PATH="$PATH:$(npm bin -g)"

API Key Issues

# Verify key is set
echo $ANTHROPIC_API_KEY

# Test with simple command
claude "Say hello"

Model Selection

# Use a specific model for a session
claude --model claude-sonnet-4-6 "Your prompt"

Terminal Power: Claude Code gives you AI assistance without leaving your terminal workflow. In the next lesson, we'll explore the agentic features that make it uniquely powerful. :::