#!perl
use strict;
use warnings;

my ($mdate,$mts) = @ARGV;
my $recent =    (map { join "-", @{$_}[0..2] . " " . join ":", @{$_}[3..5] }
                 sort { $a->[0] <=> $b->[0] || $a->[1] <=> $b->[1] || $a->[2] <=> $b->[2] }
                 map { [ split "[-: ]" ] } ($mdate,$mts))[0];
print $recent;

##</code><code>##

david@eriador ~ $ ./comparer.pl  "2006-01-01 12:00:05" "2007-01-02 12:00:00"
01 12:00:05