layermask unity not code example

Example: layermask in unity

}    void FixedUpdate()
    {
        Transform transform = Camera.main.transform;        if (Input.GetKeyUp("space"))
        {
            // Check for a Wall.
            LayerMask mask = LayerMask.GetMask("Wall");            // Check if a Wall is hit.
            if (Physics.Raycast(transform.position, transform.forward, 20.0f, mask))
            {
                Debug.Log("Fired and hit a wall");
            }
        }
    }
}