Do you mean syntax highlighting. For that there is an additional plug-in, the filter Syntax Highligher.
Visvanath Ratnaweera
Posts made by Visvanath Ratnaweera
One workaround would be to hide the course. Those with the Teacher role will still see it and can enter.
Step-by-step_Installation_Guide_for_Ubuntu is about installing Moodle which you have successfully done. Now you want to change its URL from http://example.com/moodle to http://example.com/, which is in Moodle jargon a migration. That is where Moodle_migration comes in with that Moodle_migration#Update_links_containing_wwwroot_in_the_database step.
Have you missed the Search_and_replace_tool step? A URL change is a Moodle_migration and therefore the database needs to be updated.