error: pathspec 'melodic' did not match any file(s) known to git.

[konnoeric]

I am at an installation step and encountering some error. Please help me.
I received this error when I executed git checkout melodic. What is the reason causing this issue?

error: pathspec 'melodic' did not match any file(s) known to git.

OS : Ubuntu 18.04
ROS : Melodic

[louislelay]

Hi @konnoeric, it looks like you didn't clone the repository correctly. The error in your terminal indicates that the lidar_camera_calibration directory already exists and is not empty, so the repository wasn't cloned. You should go back to ~/catkin_ws/src, remove the existing directory, and then run the git clone command again.

As a final piece of advice, no offense intended, but it's always good to check your terminal for basic errors you could troubleshoot easily before opening an issue. Seeing "fatal" in response to a git clone command is a clear sign to stop and troubleshoot before proceeding with the next installation commands.