my %found;
for my $user (in $ou) {
    push @{ $found{ $obj->{givenName} } }, $user;
}

for my $given (keys %found) {
    my $users = $found{$given};
    next if @$users < 2; # skip unique names
    print "found ".@$users." users with given name $given:\n";
    print "\t", join(', ', map { $_->{name} } @$users), "\n";
}
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