On 8/22/09, Sys Ppp <systemppp / gmail.com> wrote: > ruby-1.8.6-p369 > ruby-debug-0.10.3 > > How to set breakpoints at class-methods without editing source of > library files? And without line numbers? My recollection is that ruby-debug does not allow setting breakpoints by method name. For that, you need to use the older debug.rb (in ruby's stdlib). Add -rdebug to the command line when you start the interpreter. And you have to put up with the much slower performance of debug.rb. (Often than doesn't matter, tho.)