Dear Sir, I executed the command chmod +x my_package_launch_file.launch to give it the execution permission as it was throwing error. Still it throws error. Why?
Below is the pic attached:
Hi,
The launch files dont need execution permisions. The ones that need it are the python files executed in thelaunch files, in your case simple.py. Try to make that one executable. Also check that you have sourced the catkin_ws correctly and that you can rosrun that file without the launch file:
How to source:
cd ~/catkin_ws
source devel/setup.bash
rospack profile
How to rosrun ( always after sourcing ):
rosrun my_package simple.py
I didn’t understand it. I run this ros program and it doesn’t show me the expected output.
It throws this error below:
Why does it throw this error?
It cant find for many reasons, so we have to check if 
- Check that if you do roscd NAME_OF_PACKAGE, it take you to it
- Check that the python script is executable
- The python script is in the package you are usein in the commands