# @exec has the commad that i wish to run

  use IPC::Open3
  my $pid;

  $pid = open (WTR,T_RES,ERR,"@exec") 
    or die "Unable to fork '@exec': $!";

  while (<T_RES>) {
    # parsing the output
  }

  waitpid $pid, 0;  # if necessary, see below