Usage: program [-aDde] [-f | -g] [-n number] [-b b_arg | -c c_arg] req1 req2 [opt1 [opt2]]

This would indicate that "program" should be called with:
    - options without operands: a, D, d, e (any of which may be omitted)
      * note that in this case some parameters are case-sensitive
    - exclusive options: f, g (denoted by the vertical bar)
    - options with operands: n
    - exclusive options with operands: b, c
    - required arguments: req1, req2
    - optional argument opt1, which may be used with or without opt2
      (marked optional within the group by using another set of square brackets)
    - optional argument opt2, which requires opt1