You can conveniently store the counts of particular "words" using a hash:

#!/usr/bin/env perl
use strict;
use warnings;

my %freqs = ();
# ....
# for each match of $word
  $freqs{$word}++;
  # ...
# the list the counts:
foreach my $word (keys(%freqs)) {
  print "$word: $freqs{$word}\n";
}

1;
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