#!/usr/bin/perl

use strict;
use warnings;
use feature qw(switch say);
use Data::Dumper;

my $file = $ARGV[0] or die("Please specify a file to read\n");

if (!-e $file) {
  die("File '".$file."' doesn't exist\n");
}

my %words;

open(my $file_h, $file);
my $content = join(' ', <$file_h>);

for (split(' ', $content)) {
  $words{length($_)} = $_;
}

my @keys = sort(keys(%words));

say "The longest word was $words{$keys[-1]} with $keys[-1] characters"