my %arg_used;
        $argstr =~ s/(%(\d))/ $arg_used{$2-1}=1; defined($args[$2-1]) ? $args[$2-1] : "" /eg;
        $cmdline .= " $argstr";
        for my $i (0 .. $#args) {
            if (!$arg_used{$i}) {
                $cmdline .= " $args[$i]";
            }
        }