Install Claude Code CLI on Linux, macOS and Windows

Claude Code CLI is installed with the official installer https://claude.ai/install.sh on Linux and macOS, or winget install Anthropic.ClaudeCode on Windows, then checked with claude --version and claude doctor. You will install it on your system, complete the first launch, then check that the command works before moving on to a full workflow. The goal is a reliable, reproducible base, without getting into advanced prompting or automation scenarios yet.

What you will learn

These four points cover the whole path between a blank system and a usable session. The last two matter as much as the first two: most of the blockages reported happen after the installation, during sign-in.

• Install Claude Code CLI on Linux, macOS or Windows
• Understand the normal screens of the first launch
• Complete sign-in without getting stuck
• Check the state of the CLI with diagnostic commands

Why take care of the installation before the first workflow

A badly installed CLI produces symptoms that look like usage problems: command not found, a session that will not open, a sign-in that loops. Treating them as prompting bugs wastes time, whereas three diagnostic commands identify them in a few seconds.

This guide is therefore for people starting with Claude Code CLI who want a clean base before moving to fuller workflows. It answers one simple question: how to install, sign in and check that everything works.

It does not yet cover how sessions work, advanced prompting or governance mechanisms. Those topics are handled in the guides that follow in the course.

Prerequisites

Three things are enough. The procedure below uses neither npm nor Node.js: the official installers of each platform put the claude binary directly in your PATH.

• A local terminal (Bash, Zsh, PowerShell or equivalent)
• An account or access compatible with Claude Code: Pro, Max, Team, Enterprise, Console, or a supported API provider
• Internet access

Step 1: install Claude Code CLI

Pick the tab for your system. On Linux and macOS, the official script is downloaded, read, then run: three commands rather than a curl | bash that would blindly run whatever the network returns. On Windows, prefer WinGet, which installs a package listed in a manifest repository, over the irm … | iex form that runs a remote script directly.

Linux

# Download the official script, inspect it, then run it
curl -fsSL https://claude.ai/install.sh -o claude-install.sh
less claude-install.sh
bash claude-install.sh

macOS

# Download the official script, inspect it, then run it
curl -fsSL https://claude.ai/install.sh -o claude-install.sh
less claude-install.sh
bash claude-install.sh

Official alternative with Homebrew:

brew install --cask claude-code

To install the latest published version:

brew install --cask claude-code@latest

Windows PowerShell

Recommended method, with WinGet:

winget install Anthropic.ClaudeCode

Anthropic also publishes an installation script, run directly from the network. It works, but nothing is read before it runs: keep it for disposable machines.

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

Native Windows prerequisite: install Git for Windows before Claude Code. This prerequisite does not apply if you use WSL.

Windows CMD

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

Official alternative with WinGet (to run from PowerShell):

winget install Anthropic.ClaudeCode

Native Windows prerequisite: install Git for Windows before Claude Code. This prerequisite does not apply if you use WSL.

Step 2: check the installation

Two commands are enough: claude --version confirms that the binary is in the PATH, claude doctor checks the environment around it. Always open a new terminal before running them: the one used for the installation does not know the updated PATH yet, and that is the number one cause of the famous claude: command not found.

1. Open a new terminal (to reload the PATH)

2. Check the version

   claude --version

3. Run the basic diagnostic

   claude doctor

If the command is not found

Close the terminal completely, open a new one, then run claude --version again. If the problem persists, rerun the installation and check the messages printed at the end.

Step 3: get through the first launch

On the first claude, you will usually meet a visual setup sequence, then sign-in, before reaching a session ready to use.

Screen 1: visual setup

You land on a start screen that offers a display theme.

• Use the arrow keys to choose
• Press Enter to confirm
• You can change this choice later

Screen 2: account sign-in

The CLI then shows a sign-in URL (OAuth) and may ask for a validation code.

Recommended procedure:

1. Copy the URL shown in the terminal
2. Open it in your browser
3. Sign in to your Claude account
4. If a code is requested, go back to the terminal
5. Paste the code then confirm with Enter

Screen 3: session ready

When a "Welcome back" type of screen appears, the CLI is operational.

• The > line lets you type your requests
• The current folder shows the working context
• You can run a first simple command to check the flow

If the browser does not open

Simply copy the URL shown in the terminal, open it manually, then come back and paste the validation code if the CLI asks for it.

Step 4: a quick tour of the CLI

Once the CLI is operational, take 2 minutes to make three useful settings.

1. Open the quick help

   In the CLI session, type ? to display the available shortcuts.

2. Change the theme

   In the CLI session, type:

   /theme

   Choose a theme that is readable for you, then confirm.

3. Switch the interface language

   Open the configuration:

   /config

   Then select the interface language if the option is available in your version.

At this stage, do not try to configure everything. The goal is simply to spot where the settings you will use next are located.

Recommended next step: start with the guide Claude Code CLI: create the lab-claude running project to set up a single practice ground, then continue with Claude Code CLI: getting started, commands and configuration.

Common errors

These three symptoms cover almost all installation blockages. The first two have nothing to do with Claude Code itself: one comes from the terminal's PATH, the other from the browser. Read the "Likely cause" column before applying the fix, it avoids treating one symptom for another.

Symptom	Likely cause	Fix
claude: command not found	PATH not reloaded	Reopen the terminal, then retest
Sign-in loops	Incomplete browser session	Reuse the sign-in URL shown and finish the login
claude doctor reports warnings	Missing local dependency	Fix the blocking warnings first, then rerun

Swipe to see more

Key takeaways

Three points, and the last one is the one most often ignored: moving on to a complex workflow while the CLI is not stable produces symptoms that get blamed on the model, never on the installation.

• A successful installation is always validated with claude --version then claude doctor
• A first launch with theme + sign-in + final screen is normal behaviour
• As long as the CLI is not stable, do not chain into complex workflows

Knowledge check

Check that you have the essentials of this guide. The questions cover only what was just explained here.

Knowledge check

Check what you have learned with this interactive quiz

6 questions

6 min

70% to pass

How it works

• The timer starts when you click Start
• Multiple choice, true/false and short answer questions
• You can move between questions
• Detailed results are shown at the end

Start the quiz

Starts the quiz and the timer

FAQ: frequently asked questions

These short answers cover the points that come up most: installation under Windows and WSL, the claude: command not found message, checking the installation and the special case of npm.

How do you install Claude Code on the command line?

How do you install Claude Code on Windows?

Does Claude Code work under WSL?

Why do I get "claude: command not found" after installing?

How do you check that Claude Code is installed correctly?

Can you install Claude Code with npm?

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