warn "#1: warning";
print "#1: STDOUT is open\n";
print STDERR "#1: STDERR is open\n";
warn "#1: warning";

open FILE, '>&STDOUT';
close STDOUT;

warn "#2: warning";
print "#2: STDOUT is open\n";
print STDERR "#2: STDERR is open\n";
warn "#2: warning";

close STDERR;

warn "#3: warning";
print "#3: STDOUT is open\n";
print STDERR "#3: STDERR is open\n";
warn "#3: warning";

open STDOUT, '>&FILE';
close FILE;

warn "#4: warning";
print "#4: STDOUT is open\n";
print STDERR "#4: STDERR is open\n";
warn "#4: warning";