use Expect;
use IO::Stty;

   my  $sg_viewer = Expect->spawn("ssh -l user <IP address>");

#$sg_viewer -> log_stdout(0);

       $sg_viewer->expect( 5, '-re', "Password:" );
       sleep 1;
       $sg_viewer->send("user\n");
       $sg_viewer->expect( 5, '-re', "passwd@123" );
       sleep 1;
       $sg_viewer->send("su - root\n");
       $sg_viewer->expect( 5, '-re', "Password:" );
       sleep 1;
       $sg_viewer->send("user\n");
       $sg_viewer->expect( 5, '-re', "newroot" );
       sleep 1;
       $sg_viewer->send("su - mmadmim\n");
       $sg_viewer->expect( 5, '-re', "Password:" );
       sleep 1;

       $sg_viewer->send("attachtoprocess\n"); # this is the internal process which I am accessing... 
       $sg_viewer->interact(); # used interact module here to interact with process
       sleep 1;

       $sg_viewer->send("4"); # sending 4 as process have so many options to access the internal things.. but code is not going inside.
     

       $sg_viewer->send("exit\n");


##</code><code>##

[mmadmim@SG ~]$ attachtoprocess

--------------------------------------------------
  The process list:
  >1. BM                               00
   2. BM1                              00
   3. BM2                           00
   4. BM3                             01
   5. BM4                   01
--------------------------------------------------
   Press ESC to quit.