use strict;
use warnings;

print "about to open cat in a sub-process\n";
open(CAT, '|-', "cat") or die "open cat failed: $!";
print CAT "This was written to cat without output redirected\n";
close(CAT);
open(CAT, '|-', "cat > /dev/null") or die "open cat failed: $!";
print CAT "This was written to cat with output redirected\n";
close(CAT);
print "all done\n";