ROS2 and workspace are both just project folders where our code lives. Our shell can’t find them if we don’t source them.

#if I try to run a ros2 node without sourcing
ros2 run my_package my_node

#the shell will print as below to indicate that such command does not exist. 
#it can't track our package
ros2: command not found

Correct Steps

Suppose you have a ROS2 workspace at:

~/ros2_ws/

After building (colcon build), you do:

source ~/ros2_ws/install/setup.bash

Now your shell knows where to find the nodes, packages, and executables you just built.

Steps to Simplify Sourcing Process

• bashrc is a file that runs by default when you start a shell(terminal)
• it may be annoying to type in the whole line “source /opt…..” everytime we open a terminal,

so adding “alias” in bashrc we can make a shortcut to sourcing the workspace,

• in the above example typing “humble” in terminal sources the ros2 environment, and the “echo” prints “ROS2activated” on the terminal to indicate that the sourcing has been successful,
• the next line is for my ros2_ws, same logic…