I'm trying to learn a bit more about dtrace and I thought that using it to add probes to macruby would be fun. I pulled up the sample dtrace scripts from the Macruby 0.5 b2 source and was working with the script: class World def say(message) puts message end end world = World.new world.say('hello') (taken from http://redartisan.com/2008/5/18/dtrace-ruby) I tried to run the trace as: $ sudo dtrace -s methods_count.d -c "macruby world.rb" (where methods_count.d is one of the sample dtrace scripts) This doesn't produce any meaningful results. After playing around for a bit, I have learned that if I add a bit to the end of my ruby script: while(true) sleep 1 end What I take from that is if the ruby script runs for a longer time, dtrace has a chance plugging into the ruby application which it does not have when the script exits quickly. Am I doing something the wrong way? Is there a better way to ask dtrace to attach to my ruby application and catch information? Scott