The code the OP provides is suggestive of an approach that works if the word list is sorted.
#!/usr/bin/perl
use strict;
use warnings;
my $num_duplicates = 0;
my $last = '';
while (<DATA>) {
chomp;
if ( $_ eq $last ) {
$num_duplicates++;
}
else {
print "$_\n";
$last = $_;
}
}
print "There where $num_duplicates duplicates.\n";
__DATA__
apple
banana
banana
cherry
date
date
date
elderberry
Output:
apple
banana
cherry
date
elderberry
There where 3 duplicates.
Since the OP had the count variable, I kept it to track the total number of duplicates in the list.