You probably don't even want to use sprintf if you don't want leading zeroes. Just use double quotes. Try this:

my $x = 1;
my $y = 2;
my $str1 = sprintf "%02d %02d\n", $x, $y;
print "$str1\n";
my $str2 = "$x $y";
print "$str2\n";
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I agree with Corion though, that the date format ought to be YYYY-mm-dd if at all possible. I guess it depends on what you're using the date for...