my ($dict) = "/usr/share/dict/words";

open (FILE, $dict) or die ("Can't open $dict: $!\n");

while (<FILE>) {
    chomp;
    next if length() < 3;
    @char = split //, $_;
    $pointer = \%{$word_tree{$char[0]}};
    for (1 .. $#char) {
        $pointer = \%{$$pointer{$char[$_]}};
    }  
}

close (FILE);