Module 0: Installation

Install Claude Code

Claude Code can be installed quickly using the native installer.

Step 1: Download Claude Code

Mac / Linux / WSL

Open your terminal and run:

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

Windows

For the easiest experience on Windows, we recommend installing the Warp terminal first, which provides a modern, intuitive command line interface.

Download and install Warp from warp.dev.
Open your new Warp terminal and run the following command to install Claude Code:

Invoke-Expression ((New-Object System.Net.WebClient).DownloadString('https://code.claude.com/install.ps1'))

Step 2: Authenticate with Claude Code

The easiest way to use Claude Code is through OAuth login with your Anthropic account.

Simply open your terminal and run:

claude login

This will automatically open your web browser. Log in with your Claude.ai account or Anthropic Console credentials. Once authenticated, return to your terminal and you’re ready to go!

Option B: Using an API Key

If you prefer to use an API key manually:

Go to console.anthropic.com and navigate to API Keys.
Create and copy your key (it starts with sk-ant-).
Set it as an environment variable:

Mac / Linux / WSL:

Add this line to your ~/.zshrc or ~/.bashrc, then restart your terminal:

export ANTHROPIC_API_KEY='sk-ant-your-key-here'

Windows (PowerShell in Warp):

Run this command to set the variable for your user:

[System.Environment]::SetEnvironmentVariable('ANTHROPIC_API_KEY', 'sk-ant-your-key-here', 'User')

Important: Keep your API key private! Never share it or commit it to version control.

Step 3: Verify Installation

Run these commands to verify everything is working:

claude --version

You should see the version number (e.g., claude 2025.1.0).

Then run the diagnostic:

claude doctor

This checks that:

Claude Code is installed correctly
Your API key is valid
You have network access

Troubleshooting

”Command not found: claude”

Your shell might not have reloaded. Try:

source ~/.zshrc  # or source ~/.bashrc

Or open a new terminal window.

”Invalid API key”

Double-check that:

You copied the full key (starts with sk-ant-)
There are no extra spaces
You reloaded your shell after setting the variable

Still having issues?

Run claude doctor for detailed diagnostics, or check the official documentation.

Next Steps

You’ve installed Claude Code! In the next lesson, you’ll start Claude Code and clone the course materials.

Installation