this should do what you want (you should supply better error messages, obviously). i don't know how output redirection works in windows, but this is probably more portable anyhow.
open(B, "update blablblabl |") or die "noo! $!";
open(O, ">$temp/out.txt") or die "why me! $!";
while(<B>) { print O; }
close(B); close(O);