wb.pl

#!/usr/bin/perl

my $letters = shift or die "Specify letters";
my @letters = split //, $letters;
my $size = shift or die "Specify count";

open(DICT, "</usr/share/dict/words");

my $words = {};

while(my $word = <DICT>){
   chomp $word;
   $word = lc($word);
   $word =~ s/'//;
   $words->{$word}->{"letters"} = [split //, $word];
   $words->{$word}->{"word"} = $word;
}

for my $word ( grep { $size == @{$words->{$_}->{"letters"}} } keys(%$words) ) {
   for my $letter (@letters){
      $words->{$word}->{"word"} =~ s/$letter//;
   }
}

for my $word ( grep { $size == @{$words->{$_}->{"letters"}} and $words->{$_}->{"word"} eq "" } keys(%$words) ) {
   print "$word\n";
}