Same loop to generation to generate the arrays. Still seeing all values in the array before this:
   my @final_output;
   foreach my $line ( @output ) {
      next if ( grep m/^$line$/ @final_output );
      push @final_output, $line;
   }   
<\code>
<br>
This time I don't see 0 results, the code just hangs. At first I thought, wow, is it really that inefficient? So I decide I can do better.<br>
<br>
From a little reading about uniq I find out it essentially just slams the array values into a hash and then pulls the keys. I don't care about ordering, so why not just roll that myself?<br>
<br>
<code>
my %output_hash;
my $pk = "SomeString";
foreach my $pool ( @pools ) {
   my @machines = qx/Some command that gets me a list of machines/;
   #Some code here to check for cmd errors, etc. Convert output to an array of hashes (decode_json is involved);
   my $machine_aref = decode_json $machines[0];
   foreach my $row ( @{$machines_aref} ) {
      $output_hash{$row->{$pk}} = 1;
   }
}

my @output_array = keys %output_hash;

return \@output_array;