qq wisely pointed out a problem with a validation script I am writing for untainting purposes. The value *must* contain at least one number, but *may* also contain periods and hyphens. I *solved* it, but it look's messy. Can it be written more concisely? 
#!/usr/bin/perl -w
use strict;

my $number = "..2314-1234123.";

if ($number =~ /^((?:[0-9\.-]*)(?:[0-9]+)(?:[0-9\.-]*))$/) {
    print "$1\n";
}

[download]
Added after posting In summary, it's a regular expression that asks for at least one of a character class, but can also have some from another class.

Thanks, monks.

Update: Thanks all for participating. This was a great learning experience. If Tiger Woods were only a Perlmonk..... It seems like there is Perl and then there are regular expressions. So far Abigail-II has the lead with 16 and a reg ex that even I can understand. Now, about these 2000 lines of code I have....
Update 2: I spoke too soon, I believe Abigail-II's 2 solutions need the capturing parens to return $1--so the race is a bit tighter.

—Brad
"A little yeast leavens the whole dough."

In reply to Golf this reg ex by bradcathey

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