Quick and easy! Why go through all the ROS tutorials again when all you wanna do is save time?
Create your workspace, download the template and start developing! This simple template will get you started on any ROS project in Python under 5 minutes! What are you waiting for?
Install ROS, and make sure you execute source /opt/ros/<your version>/setup.bash. Then create your catkin workspace directory catkin_ws and initialize it with catkin init.
Inside your workspace create src directory where you will put your ROS packages.
Clone the rospy-templates repository to your src directory.
Go back to your catkin_ws and run the command catkin build.
Done!
Let's summarize all the steps into easy copy & paste commands.
source /opt/ros/<your version>/setup.bash
cd ~/
mkdir catkin_ws && cd catkin_ws
catkin init
mkdir src && cd src
git clone https://github.com/Dcasadoherraez/rospy-template.git
cd ..
catkin build
Make sure you execute roscore in another terminal by running
source /opt/ros/noetic/setup.bash
roscore
(*) Then, in your terminal, make sure your current directory is ~/catkin_ws, and source your workspace by source devel/setup.bash.
You can now run the nodes individually or using the launch file
You will need to repeat (*) for two terminals. Then run rosrun rospy-templates publisher.py on the first one, and rosrun rospy-templates subscriber.py on the second one.
This one will launch both nodes from the same terminal just by using the command roslaunch rospy-templates pub_sub.launch.