The overall process to define your own command involves several different phases, some of which are optional.
The following illustration shows the process of creating a command. The text that follows the illustration describes each phase of the process.

Writing your own validity checking and prompt override programs are optional steps.
The command definition statements contain the information that is necessary to prompt the workstation user for input, to validate that input, and to define the values to be passed to the program that is called when the command is run.