not working

i have this in package.json and it outputs PORT as empty in terminal
```sh
 "preview": "dotenv-flow -e .env -- echo $PORT",
```

.env
```
PORT=2318
```

OUTPUT
```
➜  imagen_rr git:(main) ✗ pnpm preview               

> my-react-router-app@ preview /Volumes/D/khanakia/Downloads/image_app/imagen_rr
> dotenv-flow -e .env -- echo $PORT

```