#! /usr/bin/perl -w

use strict;
use IPC::Open2;
use FileHandle;

do {
  my $pid = open2( \*Reader, \*Writer, "bash" );
  Writer->autoflush(); # default here, actually
  Reader->autoflush();
  STDIN->autoflush();
  my $cmd = <STDIN>;
  print Writer $cmd;
  my $got = <Reader>;
  print $got;
} while(1);