I was stuck on exercise 3.1 in the basics in 5 days course (Python).
Ended up pulling the solution, but still had a lot of trouble trying to make it work.
Eventually, i tried using rosrun rather than roslaunch, and it immediately made the robot move!
Is anyone able to elaborate on this? I feel like the former tutorials focused more on roslaunch, so i assumed i was to use that. Tried setting the execute privileges for both the .launch and the .py, but nothing worked.