Chapter 4: Installation

Before We Begin

Installation is the most "technical" part of this book — but it is more straightforward than it looks. You will type a few commands, and then you will be done. The whole process takes most people under ten minutes.

This chapter covers installation on Mac, Windows, and Linux. Jump to your operating system's section. If you hit any problems, the troubleshooting section at the end of this chapter covers the most common issues.

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What You Need

An account. Claude Code requires a Claude subscription (Pro, Max, Teams, or Enterprise) or an Anthropic Console account (API access with pre-paid credits). If you do not have one yet, go to claude.com and sign up before starting. The free Claude.ai plan does not include Claude Code access.

Which plan should I pick? Here is a quick comparison to help you decide before installing. You can always change your plan later.

Plan	Price	Best For	Context Window
Pro	$20/month	Occasional use, a few hours per week	200K tokens
Max 5	$100/month	Daily development, regular usage	1M tokens
Max 20	$200/month	Primary dev tool, parallel agents, heavy usage	1M tokens
API Direct	Pay per token	CI/CD pipelines, automation, bursty usage	Depends on model
Team	$25+/user/month	Team collaboration with admin controls	1M tokens
Enterprise	Custom pricing	Large organizations, compliance needs	1M tokens

Important note on Team plans: The $25/user/month Team Standard tier does not include Claude Code access. Claude Code requires Team Premium seats at a higher price point. Check claude.ai/pricing for the latest details.

Quick decision: Try the water → Pro ($20). Serious daily use → Max 5 ($100). All-in → Max 20 ($200). For a deep dive into real usage costs and leverage calculations, see Chapter 23: Cost Reality.

A terminal. This is the text-based interface you type commands into. Every computer has one built in:

• Mac: Terminal (search "Terminal" in Spotlight, or find it in Applications > Utilities)
• Windows: PowerShell or Command Prompt (search "PowerShell" in the Start menu)
• Linux: Any terminal emulator (usually accessible by pressing Ctrl+Alt+T)

An internet connection. Claude Code needs to connect to Anthropic's servers.

4 GB of RAM or more. Almost every computer made in the last ten years meets this requirement.

That is it. No other software is required for the basic installation.

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Installing on Mac

Mac installation is the simplest. Open your Terminal and run one command.

Step 1: Open Terminal

Press Command + Space to open Spotlight search, type "Terminal," and press Enter. A window will appear with a prompt — something like:

yourusername@MacBookPro ~ %

That blinking cursor is waiting for you to type.

Step 2: Run the Installer

Copy and paste this command exactly, then press Enter:

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

What does this do? It downloads the official Claude Code installer from Anthropic's servers and runs it. You will see some output as it downloads and installs. It looks something like this:

Downloading Claude Code...
Installing to /Users/yourusername/.local/bin/claude
Installation complete!
Claude Code has been added to your PATH.

The exact output may vary. As long as you do not see any red error messages, things are going well.

Step 3: Verify the Installation

Close your Terminal window and open a new one (this makes sure your system picks up the new installation). Then type:

claude --version

You should see a version number printed, like:

Claude Code 2.x.x

If you see that, installation succeeded. Move to Step 4.

Step 4: Start Claude Code

Navigate to a folder you want to work in (or just stay in your home directory for now) and type:

claude

The first time you run this, Claude Code will prompt you to log in. It will open a browser window where you authenticate with your Claude account. Follow the prompts, come back to your terminal, and you are in.

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Installing on Windows

Windows installation has two approaches. We recommend the native Windows installation, which works in PowerShell or Command Prompt. If you are already a developer familiar with WSL (Windows Subsystem for Linux), that works too.

Step 1: Install Git for Windows (Required)

Claude Code requires Git for Windows. If you are not sure whether you have it, you probably do not. Download and install it from:

https://git-scm.com/downloads/win

Run the installer. During installation, accept the defaults — you do not need to change any settings. Once it is installed, proceed.

Step 2: Open PowerShell

Click the Start menu, type "PowerShell," and click "Windows PowerShell." You do not need to run it as Administrator.

Step 3: Run the Installer

In PowerShell, run:

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

If you prefer the Command Prompt over PowerShell, use this instead:

curl -fsSL https://claude.ai/install.cmd -o install.cmd && install.cmd && del install.cmd

Wait for the installation to complete. You will see progress output in the window.

Step 4: Verify the Installation

Close your PowerShell window and open a new one. Then run:

claude --version

You should see a version number. If you do, great — move on.

Step 5: Start Claude Code

Navigate to a project folder and type:

claude

On first run, Claude Code will open a browser window for you to log in with your Claude account. Complete the login and return to PowerShell.

Alternative: WSL (Windows Subsystem for Linux)

If you already use WSL and prefer a Linux-style environment, Claude Code works great there. Open your WSL terminal and follow the Linux installation instructions in the next section. WSL 2 is recommended (it also supports Claude Code's optional sandboxing feature for enhanced security).

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Installing on Linux

Linux installation is the same single-command approach as Mac.

Step 1: Open Your Terminal

Most Linux desktops have a terminal accessible from the applications menu, or by pressing Ctrl+Alt+T.

Step 2: Run the Installer

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

For Ubuntu, Debian, and most mainstream distributions, this will work as-is. No additional dependencies needed.

For Alpine Linux and other musl-based distributions, you need to install a few additional packages first:

apk add libgcc libstdc++ ripgrep

Then run the installer.

Step 3: Verify and Start

claude --version
claude

Same as Mac — verify you see a version number, then start Claude Code and log in on first launch.

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Alternative Installation: Homebrew (Mac/Linux)

If you use Homebrew as your package manager, you can install Claude Code through it:

brew install --cask claude-code

One important note: Homebrew installations do not auto-update. When new versions of Claude Code are released, you will need to run this command to update:

brew upgrade claude-code

The native installer (the curl command above) handles updates automatically in the background, which is why we recommend it for most people.

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Alternative Installation: WinGet (Windows)

If you use WinGet on Windows:

winget install Anthropic.ClaudeCode

Same caveat as Homebrew — WinGet installations do not auto-update. Run winget upgrade Anthropic.ClaudeCode periodically to stay current.

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What Happened Behind the Scenes?

If you are curious: the installer placed a program called claude in a folder that your terminal knows how to find (usually ~/.local/bin/claude on Mac/Linux, or a similar location on Windows). When you type claude, your terminal finds and runs that program.

Claude Code stores your login credentials and settings in a folder called ~/.claude on Mac/Linux, or the equivalent on Windows. You do not need to go in there, but it is good to know it exists.

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Troubleshooting Common Issues

"command not found: claude" after installation

Your terminal does not know where to find the claude program. This usually means the installation folder is not in your system's PATH — the list of places your terminal looks for programs.

Fix: Close your terminal completely and open a new window. Installation updates the PATH, but the change only takes effect in new terminal sessions.

If a fresh terminal still shows the error, the installer may have added the PATH update to your shell configuration file (like ~/.bashrc or ~/.zshrc) but your terminal is not reading it. Try running:

source ~/.bashrc    # if you use bash
source ~/.zshrc     # if you use zsh (default on newer Macs)

Then try claude --version again.

"Permission denied" error during installation

Do not use sudo with the Claude Code installer. The installer is designed to work without elevated privileges. Using sudo can cause permission problems.

If you see permission errors, it usually means your user account does not have write access to the installation directory. The installer uses ~/.local/bin, which should always be writable by your own account. Try logging out and logging back in, then running the installer again.

"curl: command not found" on Windows

The curl command may not be available in your version of Windows. Use the PowerShell command instead:

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

Or install Git for Windows first, which includes curl.

Login does not open a browser window

Claude Code tries to open your default browser for authentication. If no browser opens:

1. Check if your default browser is set. Try opening any website manually first.
2. Look in the terminal — Claude Code may have printed a URL. Copy and paste that URL into your browser manually.
3. Make sure you have an active internet connection.

"Claude Code is not available in your region"

Anthropic's services are not available in all countries. Check anthropic.com/supported-countries for the current list of supported regions.

Installation succeeded but Claude Code is very slow on first start

The first time Claude Code starts, it downloads some additional components. This is normal and only happens once. Subsequent starts will be fast.

Getting more help

If you are stuck, run this command — it performs a diagnostic check of your installation:

claude doctor

This will tell you what is working and what is not, and often suggests how to fix the issue. If claude doctor itself does not work, check the official troubleshooting page at code.claude.com/docs/en/troubleshooting.

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You're In

Once you see the Claude Code welcome screen after running claude, you have everything you need. The hard part is done.

In the next chapter, we will walk through your very first conversation with Claude Code — from saying hello to watching it create a real file on your computer.

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Next up: Chapter 5 — Your First Conversation — Starting Claude Code, asking your first questions, and watching it take real actions.