http://musicaludi.fr/?karmanik=rencontres-antibes&c5f=67 Perl Getopt::Long.

le creusot rencontre adulte The module check wrong argument but does not check when no argument is provided.
In order to check if there is no argument as well as wrong argument,
check the argument also.

GetOptions( 'test=s' => \$option_test ) or exit(1); defined($option_test) or die("Missing argument -t");

http://www.perlmonks.org/?node_id=789974