use strict;
use warnings;
use IPC::Run qw( start );

my @c = qw( cmd /c sort );
my $h = start \@c, '<pipe', \*IN, '>pipe', \*OUT;
print IN "zzz...\n";
print IN "hello world\n";
close IN;
pump $h;
print uc while <OUT>;
close OUT;
finish $h;