Move robot / Ros / rostopic list

hello I am georgios giant study robotics 3 year now in london so i am doing a project and i watch the video about moving the robot by ros but i have question about it

if you can help me with some question so first when i try to type rostopic list it is not give me full list only a option of /rosout and /rosout_agg like it show in the picture below what is the problem what is missing ?

is any file i must creat or update in src ?

Hello @gg479,

Welcome to the community!

In your particular case I can see that there is no simulation running. So you should start first a Gazebo simulation and have a robot in the environment that subscribes to the topic /cmd_vel. So as a requisite cmd_vel must show up when you run the rostopic list command.

About the videos, we do YouTube videos and Live Classes every week explaining different ROS/robotics concepts. We also turn many of them into blog posts, which some may find easier to follow along or reproduce.
The related post for that video is here:

How to Move a Robot to a Certain Point Using Twist

Have a look at it if you get stuck and don’t hesitate to ask here at the forum if you have any other question.

And if you are new to Gazebo simulations and want to learn more about Gazebo I can recommend the course Mastering Gazebo Simulator, links:

If you are new to Python you might want to first do the free Python course on our academy.
And if you are just starting with ROS, I suggest you keep going with the ROS Basics in Five Day Course (Python).

Hope this helps you,

Regards,

Roberto

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