#!/usr/bin/perl


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

my $select = IO::Select->new();

my @commands = ("echo 1",
                "echo 2",
                "echo 3",
                "echo 4",
                "echo 5",
                );

foreach ( @commands ){

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

  my $pid = fork;
  die "Bad Fork $!" unless defined $pid;

  ### parent
  if( $pid ){
    $pipe->reader();
    $select->add( $pipe );

  ### child
  }else{
    $pipe->writer();
    $pipe->autoflush(1);

    print $pipe "PID $$: COMMAND $_\n";
    print $pipe `$_`; # do the command
    exit;
  }

}

my $num = 0;
while( my @responses = $select->can_read(0) ){
  die "Timedout [$!]\n" unless @responses;

  my $pipe = $responses[ rand @responses ];
  print STDOUT while <$pipe>;
  print "------------------------------------------------\n";

  $select->remove( $pipe->fileno() );

  last if ++$num >= @commands;
}