The ROS packages are built by the ROS build farm. We can check the status of individual packages at http://repositories.ros.org/status_page/.
Congratulations! We are done with the ROS installation. We will execute the following command to check whether the installation is correct.
Open a new terminal to run roscore:
This is followed by a turtlesim node in another terminal:
$ rosrun turtlesim turtlesim_node
If everything is correct, we will get the following screen: