1.输入roscore后报错：
Traceback (most recent call last):
File “/opt/ros/indigo/lib/python2.7/dist-packages/roslaunch/init.py”, line 257, in main
write_pid_file(options.pid_fn, options.core, options.port)
File “/opt/ros/indigo/lib/python2.7/dist-packages/roslaunch/init.py”, line 110, in write_pid_file
with open(pid_fn, “w”) as f:
IOError: [Errno 13] Permission denied: ‘/home/hdh/.ros/roscore-11311.pid’
解决方法：由于权限问题
sudo chmod 777 -R ~/.ros/
2.测试小乌龟
sudo apt-get install ros-kinetic-turtlesim
然后在打开三个不同的终端，分别输入指令：
roscore
rosrun turtlesim turtlesim_node
rosrun turtlesim turtle_teleop_key
然后就可以用键盘控制小乌龟移动了，效果如图：