Gearman comes with a few tools that make development and testing easier. The gearman program creates boilerplate clients and workers. The gearman program comes default with the gearmand package. Do not confuse gearman with gearmand. The gearmand daemon is what manages the queue, clients and workers. The gearman program is a tool to quickly create simple clients and workers. The options for gearman can be slightly confusing, so I will go through a set of examples on how to use them.
I find myself using the client functionality of the gearman tool most often. If I am tasked with creating or updating a gearman worker I want to test that the worker actually works. The code that sends a job to the worker is normally part of the web application and I don't want to dig through the application trying to figure out what I need to do send the job out. I could just create a simple php script that creates a client and sends the job over, but the gearman tool already does this.
Example of using gearman as a client:
I use the gearman program as a worker less often. It is still useful for creating a simple worker to test my client code against. I can write my client code without a fully functional worker if the client code is not expecting a complex response.
Example of using gearman as a worker:
The gearman tool comes with the standard options for specifying a specific host and port. There are a number of other options that may be of use in specific circumstances. I encourage you to read them over by typing "gearman -H" on the command line.