foreach $file (@list_of_files) {
  open FILE, "$dir/$file" || die "Can't open $dir/$file: $!\n";
  while (defined($line = <FILE>)) {
    chomp $line;
    next if ($line =~ /unknown|shutdown/);
    ($name, $ranks, $serial_numbers) = split(' ',$line);
    $HoH{$name}{$ranks} = 1;     
  }
}
[download]

Here's how I solved my problem:

Beginning file:

 open (BEGIN_FILE, "$beg_file") || die  "Cannot open: $!\n"; 
   while ($line = <BEGIN_FILE>) {
     chomp $line;
     next if ($line =~ /unknown|shutdown|NONE/);
     ($as,$as_name,$nbr,$rtr,$int,$address,$int_name,$ifindex,$vpi,$vc
+i) = split(' ',$priv_line);
     $begin{$int_name} = $rtr;
   }
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All the rest of the files:

foreach $file(@end) {
     open FILE, "$file" || die "Cannot open: $!\n";
     while ($line = <FILE>) {
       chomp $line;
      next if ($line =~ /unknown|shutdown|NONE/);
        ($as,$as_name,$nbr,$rtr,$int,$address,$int_name,$ifindex,$vpi,
+$vci) = split(' ',$priv_line);
     $end{$int_name} = $rtr;    
     }
   }
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Then, in order to end up with a hash of arrays, containing files that exist in my "non-beginning" files, but not in the beginning file:

 my  %good_files = ();
   
   foreach  $key (sort keys %end) {
     if (!exists($begin{$key})){
       push (@{$good_files{$begin{$key}}}, ($key));
       
     }
   }
[download]

Works like a charm! Thanks to everyone for their help on this.

You've got an array of items that you don't want to contain duplicates. If you store those items as the keys of a hash instead of as the elements of an array, then you will never have duplicates. That's one of the features of a hash.

So, instead of a hash of arrays, my suggestion is that you use a hash of hashes. When you want to get the list of ranks for a specific name, you would do: my @ranks = keys %{$HoH{$name}};

%hash = (a => 1, b => 1, c => 2);

%hash = reverse %hash; # key/value -> value/key
%hash = reverse %hash;

foreach $key ( keys %hash ) {
    print $key, " => ", $hash{$key}, "\n";
}
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this works to remove duplicate values but if the keys are numeric it removes the lower numbered key value pairs. how would you remove the higher key numbered key value pairs retaining the key/value pair with the lowest value key?

my $Flag = 0;
(/^$ranks$/)?$Flag++:"" foreach @{$HoL{$name}};
if ($Flag == 0) {
    push @{$HoL{$name}}, $ranks;
}
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($as,$as_name,$nbr,$rtr,$int,$address,$int_name,$ifindex,$vpi,
+$vci) = split(' ',$priv_line);
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How about this:

($rtr,$int_name) = (split(' ',$priv_line))[3,6];
[download]