Hello Wade Wilson from Python

// Die Umgebungsvariable existiert danach nicht mehr
$ python main.py

Hello World from Python
```

</div>

!!! tip "Tipp"
    Weitere Informationen dazu finden Sie unter <a href="https://12factor.net/config" class="external-link" target="_blank">The Twelve-Factor App: Config</a>.

### Typen und Validierung

This practice is common enough that it has a name, these environment variables are commonly placed in a file `.env`, and the file is called a "dotenv".

!!! tip
    A file starting with a dot (`.`) is a hidden file in Unix-like systems, like Linux and macOS.

    But a dotenv file doesn't really have to have that exact filename.