$month = '(?:Jan(?:uary)?|Feb(?:ruary)?|Mar(?:ch)?
            |Apr(?:il)?|May|Jun(?:e)?
            |Jul(?:y)?|Aug(?:ust)?|Sep(?:tember)?
            |Oct(?:ober)?|Nov(?:ember)?|Dec(?:ember)?)\s+';
$day = '[0-3]?[0-9](?:th|st|nd|rd)?,?\s+'; # I tossed an optional comma (,?) 
                                           # in there in case we have June 1st, 2000
$year = '[0-9]{2,4}';

opendir(DIRECTORY, $dir) or die "Can't open $dir: $!\n";

while($file = readdir DIRECTORY){ 
    next if $file=~/^\./; 
    $rfname=$dir . $file;
 
    open (CONT, $rfname); 
    while (<CONT>){ 
        if(/( 
               (?:${day}${month}${year}) 
               |
               (?:${month}${day}${year})
            )
        /ixo) {
            print "$1\n"; 
        } 
    } 
}