-open my $err, '>>', "$tmpdir/err.log" or die "open: err.log $!\n";
-open my $out, '>>', "$tmpdir/out.log" or die "open: out.log $!\n";
-my $rdr = { 1 => fileno($out), 2 => fileno($err) };
+my ($out, $err) = ('', '');
+my $rdr = { 1 => \$out, 2 => \$err };