Run it, then check it

Open the terminal from last chapter. Type the installer command and press enter:

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

The terminal prints a few lines as it downloads and sets things up. This takes under a minute. When it finishes, you get a fresh prompt.

Confirm it worked

Don't trust "it didn't error." Check directly. Type:

claude --version

If the install worked, this prints a version number, something like:

2.x.x (Claude Code)

A version number means the CLI is installed and your terminal can find it. That's the whole confirmation. --version is an option (you met options in the terminal chapter, a dash and a word that adjusts a command). It tells claude to just report its version and quit, which makes it a safe "are you there" check.

If it didn't work

The most common snag: you run claude --version and the terminal says something like command not found: claude. That almost always means the CLI installed fine but the terminal hasn't noticed it yet.

The fix is usually the simplest possible one: close the terminal window completely and open a fresh one. A terminal checks for available commands when it starts, so a brand-new window sees the freshly installed claude. Run claude --version again in the new window.

If a fresh window still says command not found, that's a real install issue, and Anthropic keeps a troubleshooting page for exactly this. But nine times out of ten, the fresh window is the fix. Try that first before assuming anything is broken.