@_ = (0,1,1900); 
$_ = sprintf '%4d.%02d.%02d', map {$_+pop @_} reverse +(localtime)[3..5];

# $_ = 2000.09.11 on Sept 11th, 2000.

# Another way that is more readable is:
my( $day, $month, $year ) = (localtime)[3..5];
$_ = sprintf '%4d.%02d.%02d', 1900+$year, ++$month, $day;