ROS catkin init workspace error

I encounter an error while initializing a catkin workspace. We are supposed to mkdir src in the catkin_ws folder, and then catkin_init_workspace in the src folder. Then we step out in the catkin_ws folder again and catkin_make. 

Now the error occurs, setup.sh: rm: Argument list too long, this is probably because I have sourced the setup.bash. Use another terminal to catkin_make solves this problem.