[Intro to ROS2] `ros2 run` says 'package not found' — what am I missing?

Course Help
1

Just started the Intro to ROS2 course. When I try to run a node with ros2 run <package> <executable>, I get Package '<package>' not found. Everything looked fine when I built it.

Sharing here in case others hit the same wall — what’s the first thing you check when ros2 run can’t find your package?

2

Almost always one of two things:

  1. You didn’''t source your workspace. After colcon build, you have to run source install/setup.bash in every new terminal. ROS2 only knows about packages in workspaces you’''ve sourced.
  2. The build didn’''t actually finish. Re-run colcon build from the workspace root and watch for errors — a failed build leaves the package unregistered.

Quick check: run ros2 pkg list | grep <your_package>. If it’‘‘s missing, it’’‘s one of the above. 99% of the time it’''s the source step :slightly_smiling_face: