How to test if your ros2 humble is setup

When you finish installing ros2 humble, the first thing you want to do may be test if it is setup correctly, here is an example you could follow to test.

1. Install the demo nodes

sudo apt install ros-humble-demo-nodes-py

2. source

source .bashrc

3. run talker

ros2 run demo_nodes_py talker

now you can see the talker publishing "Hello World:[num]"

4. run listener

open a new window

ros2 run demo_nodes_py listener