[getting started] specify what # and $ denotes in the prompt in unix-like OSs

guides/source/getting_started.textile

@@ -75,7 +75,7 @@ By following along with this guide, you'll create a Rails project called
 (very) simple weblog. Before you can start building the application, you need to
 make sure that you have Rails itself installed.
 
-TIP: The examples below use # and $ to denote terminal prompts. If you are using Windows, your prompt will look something like c:\source_code>
+TIP: The examples below use # and $ to denote superuser and regular user terminal prompts respectively in a UNIX-like OS. If you are using Windows, your prompt will look something like c:\source_code>
 
 h4. Installing Rails