use warnings;
use strict;

my $Fn1 = shift;
my $Fn2 = shift;

die
  "Usage:\n" .
  "hash4Ans <file1> <file2>\n\n" .
  "file1 and file2 are the files to compare\n\n"
  if ! defined $Fn1 or ! defined $Fn2;

my %File1;
my %File2;

open (inFile, "$Fn1") or die "Unable to open $Fn1 $!\n";
while (<inFile>)
  {
  chomp;
  my ($Key, $Tail) = /^((?:\w+\s){4})(.*)/g;
  $File1{$Key} = "$.:$Tail";
  }
close inFile;

open (inFile, "$Fn2") or die "Unable to open $Fn2 $!\n";
while (<inFile>)
  {
  chomp;
  my ($Key, $Tail) = /^((?:\w+\s){4})(.*)/g;
  $File2{$Key} = "$.:$Tail";
  }
close inFile;

my $Key;
foreach $Key (%File1)
  {
  next if ! defined $File2 {$Key};
  
  my ($Ln1, $Tail1) = $File1 {$Key} =~ /(\d)+:(.*)/g;
  my ($Ln2, $Tail2) = $File2 {$Key} =~ /(\d)+:(.*)/g;
  print "Match in line $Ln1 from $Fn1 with line $Ln2 from $Fn2:\n";
  print "$Key$Tail1\n";
  print "$Key$Tail2\n";
  
  my ($Words1) = $Tail1 =~ /(?:\S+\s+){3}(.*)/g;
  my ($Words2) = $Tail2 =~ /(?:\S+\s+){3}(.*)/g;
  
  print "Note: Tailing word mismatch in previous pair.\n" if $Words1 ne $Words2;
  print "\n";
  }
  
print "Done.\n";