From: Matthias Georgi <matti.georgi@...>
Date: 2006-02-24T09:53:34+09:00
Subject: Re: Q: How to initialize debugger's state when starting

A short hack.
Make a copy of debug.rb and put these lines right after the Context
class.

class Context
  alias original_readline readline
  def readline(prompt, hist)
    @rc_file ||= File.readlines("debug.rc")
    if @rc_file.empty?
      original_readline(prompt, hist)
    else
      @rc_file.shift
    end
  end
end

Now create a file debug.rc with your desired breakpoint:
b 100
b 200

Start the debugger:
ruby -r./debug myscript.rb