use Tk; 
my $stop :shared=0;
#...create Tk window

$parent-> Button(-text=>"stop", -command=>sub{$stop=1;});

$parent-> Button(-text=>"run", -command=>\&run_thread);


sub run_thread
{
    
    async{ &process; };

}

sub process
{

   open(CTFIND, "sometool find $path -print |");

   while(<CTFIND>) 
   {
       if($stop eq 1)
       {
         #close command take a while
         #close CTFIND;  This command will take a while to
         #close. It is cause any problem without close
         #pipe line?
         print"End Task\n";
              
         return;
       }

    chomp;
    #..... some date process


   }

   close CTFIND;
   return;
}