Use Getopt::Long;

Getopt::Long::Configure ("bundling");

if (!GetOptions(
            'U:s'      => \$upd,
            'mod'      => \$mod,
            'res'      => \$res,
            'h'        => \$help
   )) {
    usage();
    exit(1);
   }

if ($help) {
    usage();
    exit(1);
}

##</code><code>##

prog.pl -h

##</code><code>##

prog.pl