my $conn = MongoDB::Connection->new;
my $db = $conn->mydb || die "$!";
my ($col, $cols, @cols, $q, $doc, @b, @c, @new, $x, $date, $l, $host); 

@cols = $db->collection_names;

foreach $cols (@cols) {

##</code><code>##

if ( @new > 1 ){

		foreach my $xxx (@new){ print '@new = '.strftime('%Y-%m-%d', localtime($xxx))."\n"; }
	  $col->update( 
				 { "host" => $host },
				 {
							'$set' => {  "timestamp" => @new }
				 },
				 { 'multiple' => 1, 'safe' => 1 }
	  ) || die "$!";