How do you expect to know what any of the options means — or that they even exist — without reading the program's docs?

Scenario 1

You, as a reader of the command line, are making the *assumption* that -a is an option. The crafter of the command line should have avoided that confusion by using -cell=-a, but that doesn't excuse the negligence of the reader.

Scenario 2

You, as the crafter of the command line, don't know that -cell requires a parameter. The problem could be:

That's why it's important for the programmer to validate the input from the user. In all three cases, having something like the following would have helped: 

usage("Bad value $opt_cell for option -cell")
   unless is_valid_cell($opt_cell);

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In reply to Re^3: Issues w/ getOptions parsing options with pass_through enabled by ikegami
in thread Issues w/ getOptions parsing options with pass_through enabled by Brawny1

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