When working with Pharo Smalltalk on the commandline there is already some support in class CommandLineHandlers to retrieve arguments and options. Now Phillipe Back has improved this even further by making Ian Piumarta's GST GetOpt work in Pharo 3.0.
You can load the code from SmalltalkHub.
Getopt should be known to you if you ever work(ed) in C/C++ world. It automates some of the chore involved in parsing typical unix command line options. Java has something similar with CLI.
With Phil's project for Pharo it is now fast to use command line options and it allows also easy to debug them in the most lively environment you can work with.