#instead of
if($ssh2-> auth_password('user', 'pass')){
        print "ok";
    my $chan2 = $ssh2-> channel();
    $ssh2-> ($chan2);  #what is this step?
    print $chan2 "uname\n";
  
#try it without the if block
  $ssh2->auth_password('user','pass') or die "Unable to login $@ \n";                       
  my $chan = $ssh2->channel();                                                              
  $chan->blocking(0);                                                                       
  $chan->exec('ls -la');                                                                    
  while (<$chan>){ print }                                                                  
  #$chan->close;