#!/usr/bin/perl

if ($ARGV[0] eq $ARGV[1]) { die "Arguments are the same.\n"; }
if ($ARGV[0] gt $ARGV[1]) { die "Filenames should be in order.\n"; }


open RULE1, "<$ARGV[0]" || die "could not open $ARGV[0]\n";
open RULE2, "<$ARGV[1]" || die "could not open $ARGV[1]\n";

while(<RULE1>) {
    #feed words into some data structure
    #then close this loop
    chomp $_;
    
    @words = split;

    for $word (@words) {
        #print $word, "\n";
        while($word =~ s/\W//) {}
        $word = lc $word;
        #print "$word\n";

	$rule1{$word}++;
    }



}
#, and go through rule2 comparing words

while(<RULE2>) {

	chomp; 
	@words = split;

	for $word (@words)
	{
	     while($word =~ s/\W//) {}
         $word = lc $word;
         $rule2{$word}++;
         unless($rule2{$word} > 1) { 
	        if( $rule1{$word} > 0) {
                 $matches++;
                 $matches{$word}=1;
            }
         }
     }
}	

if($matches > 6) {
    print "I found ", $matches, " different matches between files ";
    print $ARGV[0] , " and " , $ARGV[1] , "\n" ;
    for $keys (keys %matches) {
        print $keys, "\n";
    }
}	

close RULE1;
close RULE2;