roscore
另开一个窗口：
$ ps -ef | grep /ros
roscore
rosmaster
rosoutrosnode list
rosnode info /rosout
rosnode ping rosout
rosrun turtlesim turtlesim_node
rosrun turtlesim turtlesim_node __name:=myturtle
另开一个窗口：
$ ps -ef | grep /ros
roscore
rosmaster
rosout
turtlesim_node __name:=myturtle参考： cn/ROS/Tutorials/UnderstandingNodes - ROS Wiki
