     set [ +-options ] [ +-o option name ] ... [ -A name ] [ arg ] ...
          Set the options for the shell and/or set the positional
          parameters, or declare an array.  For  the  meaning  of
          the  flags,  see OPTIONS above.  Flags may be specified
          by name using the -o option.  If the -A flag is  speci-
          fied,  name  is  set  to  an array containing the given
          args.  Otherwise the positional parameters are set.  If
          no  arguments  are  given, then the names and values of
          all parameters are printed on the standard output.   If
          the only argument is +, the names of all parameters are
          printed.
     unset name ...
          Each named parameter is unset.
