#/usr/bin/perl
use strict;
use warnings;

@ARGV == 2 or die "Must specify 2 files!\n";
my $afile = shift;
my $bfile = shift;

my $ahash = make_hash($afile);
my $bhash = make_hash($bfile);

sub make_hash {
  my $file = shift;
  my %hash = ();
  open IN, "<$file" or die "Can't open '$file': $!\n";
  while (<IN>) {
    chomp;
    my ($key,$val) = split(/,/,$_);
    $hash{$key} = $val;
  }
  return \%hash;
}

print "In A hash but not B hash:\n",
map {"$_\n"} grep {not exists $bhash->{$_}} keys %$ahash;

print "In B hash but not A hash:\n",
map {"$_\n"} grep {not exists $ahash->{$_}} keys %$bhash;

print "In A hash and B hash but different:\n",
map {"$_\n"} grep {exists $bhash->{$_} and $ahash->{$_} ne $bhash->{$_}} keys %$ahash;