A debugger for Rubinius 1.2.x

 [sudo] gem install rbx-trepanning

should get you going.

There is a google group mailing list for Ruby debuggers.

To run initially:

   $ trepanx my-ruby-program.rb

Or to call from inside your code:

 require 'trepanning' 
 debugger # Don't stop here...
 work # but stop here.

If you want an immediate stop:

 debugger(:immediate=>true)

Finally, if you put in your .trepanx

 Rubinius::Loader.debugger = proc { 
  require 'trepanning'; 
  Trepan.start(:skip_loader => :Xdebug) 
}

Then you can use the -Xdebug option the Ruby, e.g.

rbx -Xdebug my-ruby-program.rb

There is extensive on-line help. Run “help” inside the debugger.