Claude Code is Anthropic’s agentic coding tool for the terminal. It can understand a codebase, propose edits, run tests, and help with Git workflows. This guide keeps the setup simple and uses copy-ready commands.

Requirements: Ubuntu 20.04+ or Debian 10+, at least 4 GB RAM, internet access, and Node.js 18 or newer.

1. Install Node.js and Git

sudo apt update
sudo apt install -y nodejs npm git
node --version
npm --version
git --version

Expected: Each command prints a version. If Node is older than version 18, install a current Node.js release using your organization’s approved Node source before continuing.

2. Install Claude Code

Install the official package globally as your normal user. Do not use sudo npm install -g.

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

Expected: npm finishes successfully, followed by a Claude Code version number. If npm reports a permissions error, fix your npm global-prefix setup rather than rerunning with sudo.

3. Check the installation health

claude doctor

Expected: Claude Code reports its installation type and any recommended actions.

4. Start Claude Code in a project

mkdir -p ~/Projects/claude-demo
cd ~/Projects/claude-demo
git init
claude

Expected: Claude Code opens its interactive session and asks you to authenticate. Select the option matching your Anthropic Console account, Claude Pro/Max account, or approved enterprise provider. Complete the browser sign-in and return to the terminal.

5. Start with a safe prompt

In the interactive session, ask:

Explain the files in this project. Do not modify files or run shell commands.

Expected: Claude describes the repository without making changes. Review every proposed command and edit before approving it.

6. Useful everyday commands

claude "explain this project"
claude -p "list likely test commands for this repository"
claude -c
claude update
  • claude "…" starts a session with an initial prompt.
  • claude -p "…" prints a response and exits—useful in scripts.
  • claude -c continues the most recent conversation.
  • claude update requests the latest version.

7. Protect your project

Make a Git checkpoint before broad agent tasks and inspect changes afterward:

git add -A
git commit -m "Checkpoint before Claude task"
git diff
git status

Avoid --dangerously-skip-permissions unless you fully understand the command and are working in a disposable environment. The official Claude Code setup guide and CLI reference are the source of truth for current options.