updates - is it possible to upgrade to a new version via terminal?

I've noticed on a acer travelmate 5720, that runs Ubuntu 13.04, it doesn't show or pickup the latest 13.10 version. I did check die update settings and it is set pickup/show the latest updates. But with the necessary settings set, it doesn't pickup the latest version. And it does have access to full free internet. Is there some solutions? Or can I update via terminal?