What is a command on iSeries?

If you want to do something with your iSeries, you need a command on iSeries. Read Ron Turull’s review to understand the basics of iSeries commands and the command definition language.

Firstly, a command on the iSeries is an object of type *CMD. More importantly, a command on the iSeries is a program interface designed to help users call an underlying program called the command processing program (CPP) more simply. 

Especially, commands let you specify the parameters to the CPP using an easy-to-use "prompt-able" interface. A command interface for the program alleviates the need to remember all the details of the parameters when the parameters of a program become numerous and/or complicated. Commands also give you a number of validity-checking options so that parameters can be validated before the program is actually called.

What are the basics of the command definition language?

Command objects are created using a special language called the command definition language. Let’s discover 3 out of 6 command definition statements. 

1. CMD

CMD is used to introduce the command definition and specify the prompt text for the command. 

2. PARM

A PARM statement offers details about the corresponding program parameter, such as the prompt text to be displayed when the command is prompted its type and length, its name, and some basic validity-checking options.

3. QUAL

In fact, parameters have many forms. While most parameters are quite simple, others are a bit more complicated. On the iSeries, a qualified parameter is very common. For this reason, a QUAL statement is used to define the parts of a qualified parameter. It is also still required to define the parameter.

Source: Search400