Output @var{text} instead of the default greeting.
@item --help
-@itemx -h
@opindex --help
-@opindex -h
Print an informative help message on standard output and exit
successfully.
Output the traditional greeting message @samp{hello, world}.
@item --version
-@itemx -v
@opindex --version
-@opindex -v
Print the version number and licensing information of Hello on
standard output and then exit successfully.