What is the design pattern for processing command line arguments

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I think the following answer is more along the lines of what you are looking for:

You should look at applying the Template Pattern (Template Method in “Design Patterns” [Gamma, el al])

In short it’s overall processing looks like this:

If the arguments to the program are valid then
    Do necessary pre-processing
    For every line in the input
        Do necessary input processing
    Do necessary post-processing
Otherwise
    Show the user a friendly usage message

In short, implement a ConsoleEngineBase class that has methods for:

PreProcess()
ProcessLine()
PostProcess()
Usage()
Main()

Then create a chassis, that instantiates a ConsoleEngine() instance and sends the Main() message to kick it off.

To see a good example of how to apply this to a console or command line program check out the following link:
http://msdn.microsoft.com/en-us/magazine/cc164014.aspx

The example is in C#, but the ideas are easily implemented in any other environment.

You would look at the GetOpt() as just the part that fit’s into the argument handling (pre-processing).

Hope this helps.

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