my $exp = Expect->spawn("su - $username") || die "Cannot spawn su: $!\n";

#######################################
$exp->debug(3);
#######################################

$exp->raw_pty(1);
my $spawn_ok;
$exp->expect($timeout,
             [
              'Password: \$',
              sub {
                my $fh = shift;
                print $fh "$password\n";
                $spawn_ok = "yes";
                exp_continue;
              }
             ],
             [
              eof =>
              sub {
                if ($spawn_ok) {
                  die "ERROR: premature EOF in login.\n";
                } else {
                  die "ERROR: could not spawn su.\n";
                }
              }
             ],
             [
              timeout =>
              sub {
                die "Login process timed out\n";
              }
             ],
#           );
#$exp->expect($timeout,
#            [
              '-re', qr'[#>:] \$',
              sub
              {
                if($spawn_ok eq "yes")
                  {
                    if($on_off eq "on")
                      {
                        foreach $FILENAME (@list_of_files)
                          {
                            $exp->send("/bin/touch /home/$username/$FILENAME");
                            if ( $FILENAME eq ".forward")
                              {
                                #.forward must look like    \username, "|/usr/bin/vacation username"
                                $set_fwd="\\$username, \"|/usr/bin/vacation $username\"";
                                $exp->send("/bin/echo $set_fwd > /home/$username/$FILENAME");
                              }
                            if ( $FILENAME eq ".vacation.msg")
                              {
                                $message .= '\n';
                                $exp->send("/bin/echo $message > /home/$username/$FILENAME");
                              }
                            $exp->send("/bin/chmod 644 /home/$username/$FILENAME");
                            $exp->send("/bin/chown $username /home/$username/$FILENAME");
                          }
                        if($on_off eq "off")
                          {
                            foreach $FILENAME (@list_of_files)
                              {
                                $exp->send("/bin/rm -f /home/$username/$FILENAME");
                              }
                          }
                      }
                  }
              }
#            ],
#            [
#             timeout =>
#             sub {
#               die "Login process timed out\n";
#             }
#            ],
             );