How to start all the topics

Hi there, I started working on basic rosject but I am facing some problems as I am running it for the first time. I started roscore in one terminal but now when I use rostopic list, then I am getting only 2 topics, as shown in attached figure.

, how can I get all the topics such as cmd_vel and others and are there any other important commands that I need to use to set up my environment. Also, I prefer catkin build over catkin_make but I am not able to as it is showing some error as shown in second image because catkin_make is already used. How can I use catkin build again. Thanks


You have to remove the ~/catkin_ws/build and ~/catkin_ws/devel and compile again with catkin build. Because as it says in the error you compiled previously with catkin_make or at least the workspace was compiled that way.

PS: Since the workspace was previously build with catkin_make, you may continue using catkin_make. To switch between catkin_build/catkin_make, you need to remove those directories first.

cd ~/catkin_ws
rm -rf build/ devel/
catkin build
source devel/setup.bash

As for the cmd_vel and so on, those are generated with the simulation. If you don’t have any simulation running, there won’t be any topic of that kind. So, launch the simulation and check for the topics again.

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