#!/usr/bin/env perl -w

if(scalar(@ARGV) != 3){
  die "Usage: dc inputfile.txt excludefile.txt outputfile.txt \n" ;
}

my $exclude = read_hash( $ARGV[ 1 ] );
my $dict    = read_hash( $ARGV[ 2 ] );

open(OUT, ">>$ARGV[2]") or die "Error opening output file: $!\n";
open(INPUT, "$ARGV[0]") or die "Error opening input: $!\n";

while (<INPUT>) {
  @sentence = split(/\s+/);
  foreach $word (@sentence) {
    @count = split(//, $word);  ### why split before removing \W ???
    $word=~s/\W//g;

    next if @count < 4;  ### short circuit (keep nesting down); don't
                         ### need scalar
    next if $exclude->{ $word } || $dict->{ $word };

    $dict->{ $word } = 1;
    print OUT "$word\n";
  }
}
close OUT or die $!;
close INPUT or die $!;

sub read_hash {
  my $file = shift;
  open my $fh, $file or die "Error reading $file: $!\n";;
  chomp ( my @words = <$fh> );
  close $fh or die "Error closing $file: $!\n";
  return +{ map +( $_ => 1 ), @words };
}
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