Installation Beginner

Get Claude Code installed and running in just a few minutes. This guide walks you through prerequisites, installation, authentication, and your first run on macOS, Linux, and Windows.

Prerequisites

Before installing Claude Code, make sure you have the following:

Verify Prerequisites

# Check Node.js version (must be 18+)
$ node --version
v20.11.0

# Check npm version
$ npm --version
10.2.4

# Check git version (recommended but not strictly required)
$ git --version
git version 2.43.0

Install Claude Code

Claude Code is distributed as an npm package. Install it globally so you can use the claude command from anywhere.

1. Install globally via npm
   Terminal Copy

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

   Permission Error? If you see an EACCES permission error on macOS/Linux, either fix your npm permissions (recommended) or use sudo npm install -g @anthropic-ai/claude-code.
2. Verify the installation
   Terminal Copy

   $ claude --version
   claude-code/1.x.x

   If you see a version number, Claude Code is installed correctly.

Platform-Specific Instructions

macOS

# Option 1: Install Node.js via Homebrew (recommended)
$ brew install node

# Option 2: Install Node.js via the official installer
# Download from https://nodejs.org

# Then install Claude Code
$ npm install -g @anthropic-ai/claude-code

Linux (Ubuntu/Debian)

# Install Node.js via NodeSource (recommended for latest versions)
$ curl -fsSL https://deb.nodesource.com/setup_20.x | sudo -E bash -
$ sudo apt-get install -y nodejs

# Or use nvm (Node Version Manager)
$ curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.39.7/install.sh | bash
$ nvm install 20
$ nvm use 20

# Install Claude Code
$ npm install -g @anthropic-ai/claude-code

Windows (via WSL)

# Step 1: Install WSL if not already installed
PS> wsl --install

# Step 2: Restart your computer, then open Ubuntu from Start Menu

# Install Node.js inside WSL
$ curl -fsSL https://deb.nodesource.com/setup_20.x | sudo -E bash -
$ sudo apt-get install -y nodejs

# Install Claude Code
$ npm install -g @anthropic-ai/claude-code

# Navigate to your Windows project (accessible via /mnt/c/)
$ cd /mnt/c/Users/YourName/projects/my-app
$ claude

Authentication

Claude Code needs an API key to communicate with Claude. You have two options for authentication:

Option 1: Interactive Login (Recommended)

When you run claude for the first time, it will guide you through the login process.

$ claude

# Claude Code will open your browser for authentication
# Log in with your Anthropic account
# Your credentials are saved locally for future sessions

Option 2: API Key via Environment Variable

Set the ANTHROPIC_API_KEY environment variable directly:

# Set the API key for the current session
$ export ANTHROPIC_API_KEY="sk-ant-api03-your-key-here"

# Or add it to your shell profile for persistence
$ echo 'export ANTHROPIC_API_KEY="sk-ant-api03-your-key-here"' >> ~/.bashrc
$ source ~/.bashrc

First Run Walkthrough

Once installed and authenticated, here is what your first Claude Code session looks like:

1. Navigate to a project directory
   Terminal Copy

   $ cd ~/projects/my-web-app

2. Start Claude Code
   Terminal Copy

   $ claude

   Claude Code will display a welcome message and a prompt where you can type your requests.

3. Ask your first question
   Claude Code Copy

   Claude > What does this project do? Give me a high-level overview.

   Claude will read your project files and give you a summary of the codebase structure, technologies used, and main functionality.

4. Try a simple edit
   Claude Code Copy

   Claude > Add a comment at the top of README.md with today's date

   Claude will show you the proposed edit and ask for your approval before making the change.

Troubleshooting Common Issues

# Find where npm installs global packages
$ npm config get prefix

# Add the bin directory to your PATH
$ echo 'export PATH="$(npm config get prefix)/bin:$PATH"' >> ~/.bashrc
$ source ~/.bashrc

$ mkdir ~/.npm-global
$ npm config set prefix '~/.npm-global'
$ echo 'export PATH=~/.npm-global/bin:$PATH' >> ~/.bashrc
$ source ~/.bashrc
$ npm install -g @anthropic-ai/claude-code

$ nvm install 20
$ nvm use 20
$ node --version  # Should show v20.x.x
$ npm install -g @anthropic-ai/claude-code

# Set proxy for npm
$ npm config set proxy http://proxy.company.com:8080
$ npm config set https-proxy http://proxy.company.com:8080

# Set proxy for Claude Code API calls
$ export HTTPS_PROXY="http://proxy.company.com:8080"

Updating Claude Code

Keep Claude Code up to date to get the latest features and bug fixes:

# Update to the latest version
$ npm update -g @anthropic-ai/claude-code

# Check the installed version
$ claude --version

Uninstalling

# Remove Claude Code
$ npm uninstall -g @anthropic-ai/claude-code

# Optionally remove configuration files
$ rm -rf ~/.claude