That new smartphone software is a version of Ubuntu, a free Linux-based operating system for laptops, desktops, and servers. The U.K. company Canonical, which developed Ubuntu, says the first commercial handsets running the operating system will hit stores at the end of 2013. But an early version of the software will be available free in the next few weeks, along with tools for installing it on a Samsung Galaxy Nexus smartphone. The source code will also be released, allowing developers to modify the software so that it can be installed on any Android handset.