## 建立和使用環境變數

你在 **shell（終端機）**中就可以**建立**和使用環境變數，並不需要用到 Python：

//// tab | Linux, macOS, Windows Bash

<div class="termy">

```console
// 你可以使用以下指令建立一個名為 MY_NAME 的環境變數
$ export MY_NAME="Wade Wilson"

// 然後，你可以在其他程式中使用它，例如
$ echo "Hello $MY_NAME"

Hello Wade Wilson
```

</div>

////

//// tab | Windows PowerShell

<div class="termy">

```console
// 建立一個名為 MY_NAME 的環境變數

Ambas *path operations* requieren un `X-Token` header.

//// tab | Python 3.10+

```Python
{!> ../../docs_src/app_testing/app_b_an_py310/main.py!}
```

////

//// tab | Python 3.9+

```Python
{!> ../../docs_src/app_testing/app_b_an_py39/main.py!}
```

////

//// tab | Python 3.8+

```Python
{!> ../../docs_src/app_testing/app_b_an/main.py!}
```

Обидві операції шляху вимагають заголовок `X-Token`.

//// tab | Python 3.10+

```Python
{!> ../../docs_src/app_testing/app_b_an_py310/main.py!}
```

////

//// tab | Python 3.9+

```Python
{!> ../../docs_src/app_testing/app_b_an_py39/main.py!}
```

////

//// tab | Python 3.8+

```Python
{!> ../../docs_src/app_testing/app_b_an/main.py!}
```

Both *path operations* require an `X-Token` header.

//// tab | Python 3.10+

```Python
{!> ../../docs_src/app_testing/app_b_an_py310/main.py!}
```

////

//// tab | Python 3.9+

```Python
{!> ../../docs_src/app_testing/app_b_an_py39/main.py!}
```

////

//// tab | Python 3.8+

```Python
{!> ../../docs_src/app_testing/app_b_an/main.py!}
```

Wir hatten diese Typannotation:

//// tab | Python 3.10+

```Python
q: str | None = None
```

////

//// tab | Python 3.8+

```Python
q: Union[str, None] = None
```

////

Wir wrappen das nun in `Annotated`, sodass daraus wird:

//// tab | Python 3.10+

```Python
q: Annotated[str | None] = None
```

////

//// tab | Python 3.8+

```Python

**터미널을 새로 열고** 프로젝트 작업을 시작할 때는, **항상 이 작업을** 해주세요.

///

//// tab | Linux, macOS

<div class="termy">

```console
$ source .venv/bin/activate
```

</div>

////

//// tab | Windows PowerShell

<div class="termy">

```console
$ .venv\Scripts\Activate.ps1
```

</div>

////

//// tab | Windows Bash

//// tab | Uvicorn

<div class="termy">

```console
$ uvicorn main:app --host 0.0.0.0 --port 80

<span style="color: green;">INFO</span>:     Uvicorn running on http://0.0.0.0:80 (Press CTRL+C to quit)
```

</div>

////

//// tab | Hypercorn

<div class="termy">

```console
$ hypercorn main:app --bind 0.0.0.0:80

У нас была аннотация следующего типа:

//// tab | Python 3.10+

```Python
q: str | None = None
```

////

//// tab | Python 3.8+

```Python
q: Union[str, None] = None
```

////

Вот что мы получим, если обернём это в `Annotated`:

//// tab | Python 3.10+

```Python
q: Annotated[str | None] = None
```

////

//// tab | Python 3.8+

```Python

//// tab | python 3.9+

```python hl_lines="6  14  22"
{!> ../../docs_src/dependencies/tutorial008_an_py39.py!}
```

////

//// tab | python 3.8+

```python hl_lines="5  13  21"
{!> ../../docs_src/dependencies/tutorial008_an.py!}
```

////

//// tab | python 3.8+ non-annotated

/// tip | Dica

Teníamos esta anotación de tipo:

//// tab | Python 3.10+

```Python
q: str | None = None
```

////

//// tab | Python 3.8+

```Python
q: Union[str, None] = None
```

////

Lo que haremos es envolver eso con `Annotated`, para que se convierta en:

//// tab | Python 3.10+

```Python
q: Annotated[str | None] = None
```

////

//// tab | Python 3.8+

```Python