## Commands

Widgets in guizero can be given a `command` when created, which can be used to call a function when the widget is used.

By using commands you can make your GUI change and take actions when the user interacts with it, for example by clicking a button, selecting an option or typing a message.

### Example

This code will display `hello world` when the button is pressed:

    from guizero import App, Text, PushButton

    def say_hello():
        text.value = "hello world"

    app = App()
    text = Text(app)
    button = PushButton(app, command=say_hello)
    app.display()