sub foo {
  my $rc = 0;

  if (!$ssh->start_session($ssh_host)) {
      print "ERROR connecting to $ssh_host\n";
      $rc = 1;
      goto end;
  }

   my ($ret,$err)=$ssh->execute('command1','expect1');
   if ($err || $ret=~/Unknown command:/m) {
       $rc = 2;
       goto cleanup;
   }

   my ($ret,$err)=$ssh->execute('command2','expect2');
   if ($err || $ret=~/Unknown command:/m) {
       $rc = 3;
       goto cleanup;
   }

   ...

cleanup:
  $ssh->exit_session();
  $ssh->close_session;

end:
  return $rc;
}