#!usr/bin/perl -w 
use strict;

open FILE, '<', "input.txt" or die "unable to open input.txt";
# the $! variable adds the O/S specific info, but it is not
# not always that useful.

my @all_words;

while (<FILE>) 
{ 
   my @these_words = split(' ', $_);
   foreach my $this_word (@these_words)
   {
      push @all_words, $this_word;
   }
}
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#to count the words:
use Data::Dumper;
my %words;
while (<FILE>) 
{ 
   my @these_words = split(' ', $_);
   foreach my $this_word (@these_words)
   {
      $words{$this_word}++;
   }
}
print Dumper \%words;
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