Here's a proper (tested), efficient, in-place, pure Perl, Fisher Yates shuffle:

sub shuffleAry {
    die 'Need array reference' unless ref( $_[0] ) eq 'ARRAY';
    our( @aliased, $a, $b ); local( *aliased, $a, $b ) = $_[0];

    $a = $_ + rand @aliased - $_,
    $b = $aliased[ $_ ],
    $aliased[ $_ ] = $aliased[ $a ],
    $aliased[ $a ] = $b
        for 0 .. $#aliased;
    return;
}

my @array = 1..100;

shuffleAry( \@array );

print @array;
[download]