#!/usr/bin/perl
use warnings;
use strict;

use IO::Handle;
use IO::Pipe;
use IO::Select;

my $stdout = IO::Pipe->new();
my $stdin  = IO::Pipe->new();

defined(my $pid = fork) or die "Fork failed\n";

if($pid) {
  $stdout->reader();
  $stdin ->writer();
  $stdin ->autoflush(1);
  my $select = IO::Select->new($stdout);
  foreach my $key (@ARGV) {
    $stdin->print("parent ($$) send [$key]\n");

    next unless $select->can_read(1);
    $stdout->sysread(my $buf, 1024);
    chomp($buf);

    print "parent ($$) recv [$buf]\n";
  }
  $stdin->close();
  waitpid($pid, 0);
} else {
  $stdout->writer();
  $stdin ->reader();
  $stdout->autoflush(1);
  open STDOUT, ">&", $stdout;
  open STDIN, "<&", $stdin;
  exec "$^X", "tst.pl";
}

##</code><code>##

#!/usr/bin/perl
use warnings;
use strict;

$|++;

while(<STDIN>) {
  chomp;
  next unless /\[(\d+)\]/ && $1 % 2 == 1; # Only odds
  print "$1 is odd\n";
}