#!/usr/bin/perl -w
use strict;

my %month2numstring = (Jan => '01',
                       Feb => '02',
                       Mar => '03',
                       Apr => '04',
                       May => '05',
                       Jun => '06',
                       Jul => '06',
                       Aug => '08',
                       Sep => '09',
                       Oct => '10',
                       Nov => '11',
                       Dec => '12', );

while (<DATA>)
{
   my $datefield = (split)[3];
   my ($datestring) = $datefield=~ m|\[([\w/:]+)|;
   
   my $new_date_field = reformat_date_time($datestring);
   
   print "$new_date_field\n";
}

sub reformat_date_time
{
    my $date_time = shift;
   
    my ($date,$time) = m|([\w/]+):([\d:]+)|;
    my ($day,$month_text,$year) = split(m|/|,$date);
    
    $day = "0$1" if $day =~ m|^(\d)$|;      #force leading zero
    my $month = $month2numstring{$month_text};
    
    return ($year.'-'.$month.'-'.$day." $time");
}

=prints
2010-08-21 00:00:00
2010-08-21 00:01:00
2010-08-22 01:00:00
2010-08-22 02:00:00
2010-08-22 03:04:00
=cut

__DATA__
67.162.10.216   -       -       [21/Aug/2010:00:00:00   +0000]  GET /2010-08-18/news/ct-met-barrington-student-death-20100818_1_mental-illness-suicide-prevention-teen-suicides HTTP/1.1        200     6826 
67.162.10.216   -       -       [21/Aug/2010:00:01:00   +0000]  GET /2010-08-18/news/ct-met-barrington-student-death-20100818_1_mental-illness-suicide-prevention-teen-suicides HTTP/1.1        200     6826 
67.162.10.216   -       -       [22/Aug/2010:01:00:00   +0000]  GET /tracker.js.php?45aa01ed37b58d2a537b1ba12bb97fe2e5695a8c HTTP/1.1   200     2915
67.162.10.216   -       -       [22/Aug/2010:02:00:00   +0000]  GET /tracker.js.php?45aa01ed37b58d2a537b1ba12bb97fe2e5695a8c HTTP/1.1   200     2882
66.249.71.98    -       -       [22/Aug/2010:03:04:00   +0000]  GET /ad-openx.php?out=js&d=mod-top-hdr-defer&z-i=24809&z-n=top-...blah....