If you think that typing in all of these parameters list by hand, instantiating classes and creating files is a bit tedious, you're right! For times when you have many jobs to run off as a batch process, or just want to play around a bit you really need something more suited to that task. To cater to this need, the wrapper are able to be run from the command line.
Every wrapper support the same command line arguements; there are only three.
<wrapper_name> parameter_file input_filename output_filename