[CLI] required options vs. usage

["Sigler, John" <Jo...@sabre.com>]

I'd like to set some options as required command line arguments, which are required _except_ when someone wants to see the usage text. That is, the command:

  foo

throws a missing argument exception (and probably prints usage) because there were missing required switches of "-s -f filename" switch. And:

  foo -s -f file -o -g -l

works because -s and -f file match the required options (and the others weren't). And:

  foo -h

prints usage and exits and ignores the required arguments.

I'd think this is fairly common but the only way I see to do this is not use required options and handle that logic myself. Am I missing something obvious?

john