Well, you can improve your regex to /^[rgtnaie]{9}$/. If you wanted to, you could also do something like:

my $charclass = "aeginrt";
my $num = 9;
if (/^[$charclass]{$num}$/) {
# rest of code here
[download]

That way, you can easily change what it is you're working with. Of course, that doesn't help you with determining if it has the right amount of the right letters. So, you could do something like:

my %num_letters = ( a => 1,
                    e => 2,
                    g => 1,
                    i => 1,
                    n => 1,
                    r => 1,
                    t => 2,
                  );

my $charclass = join "", keys %num_letters;
my $num_chars = 0;
$num_chars += $num_letters{$_} foreach keys %num_letters;

open DICT, "<linux.words";
WORD:
while (my $word = <DICT>) {
    my %letters = %num_letters;
    chomp $word;
    next WORD unless $word =~ /^[$char_class]{$num_chars}$/;

    while (my $letter = chop($word)) {
        $letters{$letter}--;
    }
    foreach my $letter (keys %letters) {
        next WORD if ($letters{$letter} != 0);
    }
    print "Found $word\n";
}
close DICT;
[download]

------
/me wants to be the brightest bulb in the chandelier!

---

---

• Are you posting in the right place? Check out Where do I post X? to know for sure.
• Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:

  <code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>

• Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
• Want more info? How to link or How to display code and escape characters are good places to start.