#!/usr/local/bin/perl -w
#### A ####
use IPC::Open2;
open2( \*READ, \*WRITE, '/home/random/B' );
print WRITE "Hello there.\n";
my $in=<READ>;
print "$0 read: $in\n"

#!/usr/local/bin/perl -w
#### B ####
$input = <STDIN>;
print "echo back: $input";