# Where Am I Typing?

Your work in this course happens in four windows. Commands go in only one of them, VS Code's Terminal, and inside it two different programs can be reading what you type. A command that works in one place fails in another, and the error does not tell you which place you meant.

## Which window is which

| Window | What you do there | You know it by |
|---|---|---|
| **GitHub Desktop** | Commit and push | A **Commit to main** button, bottom left |
| **VS Code** | Everything in your course folder: edit files, run commands in the **Terminal** panel, add extensions | Your files listed on the left |
| **marimo**, in your browser | Write and run your notebook | An address starting `localhost` |
| **github.com**, in your browser | See what you pushed | An address starting `github.com` |

marimo and github.com both open in your browser, so look at the address bar to tell them apart.

## Which prompt is which

In VS Code's Terminal, the text just before your cursor is the prompt. It tells you which program will read the next thing you type.

| You see | You are in | What you can type |
|---|---|---|
| `PS C:\...\<course-code>>` | PowerShell in VS Code's Terminal, on Windows | Commands, such as `uv run marimo edit` |
| `you@laptop <course-code> %` | VS Code's Terminal, on macOS | Commands, such as `uv run marimo edit` |
| `>>>` | The Python interpreter | Python only. Type `exit()` to leave |

`<course-code>` stands for your repository's name, `oim7510` or `oim6301`.

**Purple text after a line of Python** is Python reporting an error. Read its last line first. Errors from PowerShell itself, such as a program it cannot find, print in red.

## A command typed at `>>>`

Python tries to read the command as Python and prints a few lines, ending in this one:

```
SyntaxError: invalid syntax
```

Type `exit()` and press Enter. The prompt changes back to `PS` or `%`, and the same command works there.

You will also see the `>>>` prompt called the REPL, in documentation and in answers from an agent.

For errors from the commands themselves, see [The Terminal](/guides/terminal/).