Claude Code: AI in Your Terminal
You install and use Claude Code CLI for code assistance and automation.
Why this lesson matters
By now you know Claude as a chat interface. You type a prompt, get an answer, copy it into your project. But what if Claude could work directly in your codebase? Read files, change them, make commits, run tests, all from your terminal?
That's exactly what Claude Code does. It's a CLI tool (command line interface) that puts Claude in your terminal as an AI agent. No more copy-paste. No lost context. Claude works directly with your files, understands your project structure, and carries out tasks as if it were a smart colleague sitting next to you.
Understanding what Claude Code can do helps you use AI workflows at a fundamentally different level.
What is Claude Code?
Claude Code is Anthropic's official CLI tool. It runs in your terminal with direct access to your files.
| Property | Claude Chat | Claude Code |
|---|---|---|
| Interface | Browser | Terminal |
| Reading files | Upload or paste | Reads straight from disk |
| Editing files | Copy the output | Changes files directly |
| Project context | Whatever you paste | Whole codebase available |
| Git integration | None | Commits, branches, PRs |
| Multiple files | Awkward | Easy |
Claude Code is an autonomous agent. You give it a task, and it works out for itself which files it needs to read and which changes are needed, then carries them out with your permission. You start it in your terminal. It also runs as a desktop app for Mac and Windows, on claude.ai/code, and as an extension in VS Code and JetBrains.
Keep reading
Leave your name and email address and you can read the rest
You get the whole lesson right away, and every other lesson stays open after that. No password, no confirmation email.
What it means in practice
The most powerful aspect of Claude Code is direct file access. Claude can:
Read: open files, search folders with patterns, search contents with regex, look at images and PDFs.
Edit: make text replacements, create new files, change several files at once, refactor across your whole codebase.
> Find all TODO comments in the src/ folder
> Replace all console.log statements with a proper logger
> Add TypeScript types to the API functions in services/Claude Code always asks permission before it changes files. You see exactly which changes are proposed and you have to approve them. Nothing gets changed behind your back.
When Claude Code vs. Claude Chat?
| Situation | Use |
|---|---|
| Quickly write a text or brainstorm | Claude Chat |
| Analyse a complex document you upload | Claude Chat |
| Make changes in a codebase | Claude Code |
| Refactor several files at once | Claude Code |
| Automate a git workflow | Claude Code |
| Test a prompt with different inputs | Claude Chat |
| Hunt a bug across several files | Claude Code |
| Write an email or report | Claude Chat |
Rule of thumb: if your task involves files on your computer, pick Claude Code. If it's about generating or analysing text without file context, Claude Chat is faster and simpler.
Practice exercise
Take the table above and walk through your own working week.
- 1Write down 5 tasks you did with AI last week, or would have liked to
- 2Next to each task, note whether it's about text or about files on your computer
- 3Count how many are in the second column
If more than half are, your work sits in the area where a tool with file access saves you time. If there's almost nothing there, you'll get more out of better prompts in the chat window.
What is the main difference between Claude Chat and Claude Code?
You need to summarise a 40-page report that's sitting in your mail as a PDF. Which tool is the obvious choice?
Want to keep your progress, get the practice files and sign up for the free evening? Create a free account. All you do is click a link in your email.
Create a free account