back` function, changes can be accessed from within the target function,
    using the `WATCHFILES_CHANGES` environment variable.

    ```py title="Example of run_process accessing changes"
    from watchfiles import run_process

    def foobar(a, b, c):
        # changes will be an empty list "[]" the first time the function is called
        changes = os.getenv('WATCHFILES_CHANGES')
        changes = json.loads(changes)
        print('foobar called due to changes:', changes)

    if __name__ == '__main__':
        run_process('./path/to/dir', target=foobar, args=(1, 2, 3))
    ```

    Again with the target as `command`, `WATCHFILES_CHANGES` can be used
    to access changes.

    ```bash title="example.sh"
    echo "changers: ${WATCHFILES_CHANGES}"
    ```

    ```py title="Example of run_process running a command"
    from watchfiles import run_process

    if __name__ == '__main__':
        run_process('.', target='./example.sh')
    ```
    r