The following explains how to demonstrate the woof.d DTrace script. This script is only useful if you have an audio device, /dev/audio. To test audio, you can run: $ audioplay /usr/share/audio/samples/au/sample.au The volume can be adjusted from a few tools, including, $ /usr/dt/bin/sdtaudiocontrol ... woof.d will bark whenever a new process is created. In order to demonstrate it, first run the following: # ./woof.d & You have now installed the dog (if the dog becomes a nusience, you are allowed to kill it). Now compare the difference between these recursive grep commands: $ find /etc -type f -exec grep localhost {} \; $ find /etc -type f -exec grep localhost {} + The first find command is the "bad way", the second is the "good way". You will hear for yourself why this is the case.