# I didn't have the length == 8 line because
# I'm only reading one file containing 8-letter words
while (<FH>) {
  $c = substr ($_, 2, 1);
  if (substr ($_, 5, 1) eq $c) {
    my %h;
    @h{split//,$_} = (1) x 8;
    print if keys %h == 7; 
  }
}