Tell me what happens when you run this:

open(MFOUT,">mfout.txt");

my @commands= (
'echo "Hello1"',
'echo "Hello2"',
'echo "Hello3"',
'echo "Hello4"',
'echo "Hello5"',

);

my %running = ();
my $max_jobs = 2;
my $job_count = 0;

while ( @commands || %running )
{
  if ( @commands && ($job_count < $max_jobs))
  {
    my $command = shift(@commands);
    my $pid;
    if ($pid = fork)
    {
         print "Parent Pid $$\n";
         $running{$pid} = $command;
         ++$job_count;
    }
    else
    {
         die "cannot fork: $!" unless defined $pid;
         print "Child Pid $$ $command\n";
         print MFOUT `$command`;
         my $rc = system $command;
         exit($rc>>8);
    }
  }
  else
  {
   my $child_pid = wait();
   if (! exists $running{$child_pid})
   {
     warn "Reaped unkown process id $child_pid!!";
   }
   elsif ($?)
   {
     my $rc = $? >> 8;
     warn "Process '$child_pid:$running{$child_pid}' errored with retu
+rn code '$
rc'";
   }
   print "command '$running{$child_pid}' completed\n";
   delete $running{$child_pid};
   --$job_count;
  }
}


print "The end!\n";
print MFOUT "The end!\n";

[download]

____________________
Jeremy
I didn't believe in evil until I dated it.

In reply to test this by jepri
in thread fork and print.. by Kung

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