$ cat test-gol.pl
#!/usr/bin/perl
use Getopt::Long qw/:config pass_through/;
my ($array, @array);
# option names are: [sa][nw] s=scalar, a=array n=no '@', w=with '@'
GetOptions( 'sn=s' => \$array ) or die 'options';
print "Scalar @$array\n"; undef $array;
GetOptions( 'sw=s@' => \$array ) or die 'options';
print "Scalar @$array\n";
GetOptions( 'an=s' => \@array ) or die 'options';
print "Array @array\n"; @array = ();
GetOptions( 'aw=s@' => \@array ) or die 'options';
print "Array @array\n";

$ perl test-gol.pl --sn one --sn two --sw one --sw two --an one --an two --aw one --aw two
Scalar
Scalar one two
Array one two
Array one two