#!/usr/bin/perl

use strict;
use Data::Dumper;

my (@total_words, %record_file_of);
my $counter = 0;
my $num_of_files = 3;

@total_words = split while (<DATA>);

my $words_per_file = int( scalar @total_words
  / $num_of_files );

for my $i (0 .. $#total_words) {
    $counter++ if ( $i % $words_per_file == 0 );
    push( @{ $record_file_of{$counter} }
      , $total_words[$i] );
}

print Dumper \%record_file_of;

__DATA__
This is a test of words. This should be divided into equal files.