#!/usr/bin/perl
use strict;
use warnings;
use IO::Pty;
use IO::Select;
use POSIX qw(:sys_wait_h);
use Data::Dumper;

my $timeout = 5;
my @cmd=('perl', '-e', 'for(0..2){print qq(TEST $_\n); warn(qq(TTTT $_\n)); sleep(1); }');

my $output='';

# create virtal terminal
# imortant for applications with terminal detection!
my $pty = IO::Pty->new();

# split in two independent processes
my $pid = fork();

# fork failed!
die('Fork failed!') unless(defined($pid));

if($pid)
{
  # main process!

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

  my $time=time()+$timeout;

  # wait timeout seconds
  while($time > time())
  {
    # is process running?
    if(waitpid($pid, WNOHANG) == 0)
    {
      # read if possible
      $output.=<$pty> if($select->can_read(1));

      # do something else
      print "WAIT\n";
      # ...
    }
    else
    {
      # exit while loop
      last();
    }
  }

  # process running?
  if(waitpid($pid, WNOHANG)==0)
  {
    print "TIMEOUT KILL PROCESS\n";
    # force exit (softly)
    kill(9, $pid);
    $output='';
  }
}
else
{
  # forked process!

  # virtual terminal client
  my $slave = $pty->slave();
  close $pty;
  $slave->clone_winsize_from(\*STDIN);
  $slave->set_raw();

  # reopen STDOUT and STDERR
  open(STDOUT, ">&", $slave);
  open(STDERR, ">&STDOUT");
  close($slave);

  # start programm with actual process id
  exec(@cmd);

  # error???
  die("EXEC Failed! ($!)");
}

if($output)
{
  print "OUTPUT:\n";
  print $output;
}
else
{
  print "NO OUTPUT!\n";
}