Thank you LanX for your replies, I did mean using the debugger non-interactively (i.e. using environment variables/cmdline args to tell the debugger which variables should be printed when executed non-interactively).

Laurent_R thank you for your reply detailing some ways of printing variables from the interactive debugger, if you would like additional description of a case which might require non-interactive debugger usage please read the update within the original question.