roscd beginner_tutorials 时提示beginner_tutorials不是一个package解决:在ros_workspace[实际路径]下再次source ./devel/setup.hrosmsg show Num 时提示could not find msg Num解决:export ROS_PACKAGE_PATH=~/catkin_ws/src/tutorials:$ROS_PACKAGE_PAT~/catkin_ws/src/tutorials为自己packag.