$stuff="0.4312342134234234";
$morestuff="0.2432134234342342";

open(F,'>'.'/tmp/foo1.txt');

printf(F << "__EOFOO__", $stuff, $morestuff);
Some stuff: %.4f
Some more stuff %.4f
__EOFOO__

close(F);

##</code><code>##

$stuff="0.4312342134234234";
$morestuff="0.2432134234342342";

$fh=IO::File->new(">/tmp/foo2.txt");
printf($fh << "__EOFOO__", $stuff, $morestuff);
Some stuff: %.4f
Some more stuff %.4f
__EOFOO__