Debug history, a la irb/ext/save-history

Having just now stumbled across setting up .irbrc to store IRB history
– is
there something similar for the debug module? Such that in between debug
sessions I can access previous commands issued in the last session?
(esp.
handy for setting breakpoints, now that rubygems consumes the first step
into the script, rather than the current file).

(XP, Ruby 1.8.4)