If you have ever accidentally closed a terminal window which was running your Rails Webrick server and the server continued to run in the background but you need to kill it so you can restart a new instance you can do the following:
1. run the lsof command identifying port 3000 as the target to get the process ID of the rouge Webrick server
2. then use the kill command plus the process ID you got from step 1 and your rouge will be taken care of.
Of course this is just one way to handle it, if anyone has a better way please comment and let the rest of us know. Thanks in advance!