~/ $ mkdir catkin_ws/src
~/ $ cd catkin_ws/src
~/catkin_ws/src $ catkin_create_pkg beginner_tutorials std_msgs rospy roscpp

// This will generate the following file structure ...
~/catkin_ws
  |- src
     |-beginner_tutorials
        |- CMakeLists.txt
        |- include
        |- package.xml
        |- src