Chris asked: > commands ... anyone > know of a reference in English? Yup, I know. I "translated" it some time ago. Anyway, it's pretty much the same as in Perl. Try ruby -v -rdebug -e'1;' > h [niemela@mercury ruby]$ ruby -v -rdebug -e'1' ruby 1.6.2 (2000-10-16) [i686-linux] Debug.rb Emacs support available. -e:1: warning: useless use of a literal in void context -e:1:1 (rdb:1) h Debugger help v.-0.002b Commands b[reak] [file|method:]<line|method> set breakpoint to some position It has been incorporated to standard Ruby some time ago. If it's not on your ruby, please find the posted patch from mailing list archive, and patch by yourself, or update your version of Ruby. I'd do the latter :). Also, I'd like to say I still haven't done anything with irb, so for that I can't help at all. But they say it's better to use irb instead of debug.rb, so beware of There's Always a Better Way To Do It :). - Aleksi