setup files of ros are set in setup.bash and have to be sourced everytime a terminal is open

/opt/ros/humble/setup.bash

Using ~/.bashrc

.bashrc is a file that runs by default when a terminal/shell is open. I will edit this to make the process of sourcing simpler

1. Open your bashrc:

nano ~/.bashrc

1. Add at the very bottom:

alias humble="source /opt/ros/humble/setup.bash && echo 'ROS2 Humble activated ✅'"

#alias - shortcut for long command, allows to just type humble to activate the green part

#source - runs a script

#echo - just like print() but in terminal

1. Save and open new terminal, now your new terminal has the changes applied
2. Now just type:

humble

👉 and it’ll source ROS2 Humble for you, plus print ROS2 Humble activated ✅.