The command-line function is only available for registered users.
Honestly I don't know how it works. I've never worked with it before.
The way I would set up a panorama is to increase the fov in the camera-setup and render the image at 16:9 or 2:1 ratio, something like that.
For ways to use the command-line renders, and all other questions, I'd advice to use the search function. The forums already contain a tremendous amount of information on almost any subject.
(n.b. sometimes the search function doesn't return results surprisingly, performing the search again will often return results (don't know why, but it works for me here))