From: "Rocky B." Date: 2011-02-04T10:05:38+09:00 Subject: Re: Strange "ruby -r debug t.rb" for PickAxe ver. 2's Fibonacci example The Ruby program debug.rb which comes with Ruby 1.x is what you get when you run "ruby -rdebug t.rb" or "ruby -r debug t.rb". (You have a typo in the first example with the flag -t). ruby-debug, which installs a bin/rdebug to invoke the debugger from the outset, is something totally different. In contrast to debug.rb, ruby-debug is not part of the standard Ruby distribution. That is why you install it as a gem as you list above. The pickaxe books talk about debug.rb, not the ruby-debug gem. I think it safe to say that most folks who use any sort of debugger are nowadays using ruby-debug. (Even the IDE's like the ones from Eclipse, JetBrains, or Aptana use common code from ruby-debug and none import any code from debug.rb) ruby-debug commands are largely a superset of the debug.rb command listed in the Pickaxe book. However more complete information on ruby-debug can be found at http://bashdb.sourceforge.net/ruby-debug.html I realize all of this is confusing. Unfortunately it is a bit too late to change this in any significant way. In the next round of debuggers, the "trepanning" debuggers, (e.g. http://github.com/rocky/rb-trepanning and http://github.com/rbx-trepanning) I've tried to make the distinction more clear. The command-line invocation is not "rdebug" which can be confused with the command-line option -rdebug. And the prompt which had been (rdb) is now different. -- Posted via http://www.ruby-forum.com/.