use Expect;
$Expect::Debug = 1;    # verbose debug output
$Expect::Log_Stdout = 1;  # show chatter for debugging

# stolen from Net::Telnet::Cisco I think.
my $prompt = '[\w-]+\s?(?:\(config[^\)]*\))?\s?[\$#>]\s?(?:\(enable\))?\s*$';

my $exp = Expect->spawn( @command );
# or
my $exp = Expect->exp_init($filehandle);

sub cmd { my ($exp, $cmd) = @_;
 $exp->print($cmd, "\n");
 $exp->expect($timeout, -re => $prompt) or return;
 my $output = $exp->before;
 $output =~ s/\r//g;  # silly telnet line endings
 $output =~ s/^$cmd\n//;  # remove the sent cmd
 return $output;
}

sub login { my ($exp, $user, $pass) = @_;
 my $rc = $exp->expect($timeout,
  [qr/[Pp]assword:\s*/, sub { my $exp = shift;
   $exp->print($pass,"\n");
   exp_continue;
  }],
  [qr/[Uu]sername:\s*/, sub { my $exp = shift;
   $exp->print($user,"\n");
   exp_continue;
  }],
  -re => $prompt,
 );
 return defined($rc) ? $rc : 0;
}

sub enable { my ($exp, $pass) = @_;
 $exp->print("enable","\n");
 $exp->login('',$pass);
}

# generic chat once you have your $exp from a spawn or filehandle

login($exp, "username", "password");
cmd($exp,"terminal length 0");
enable($exp, "enablepass");
my $config = cmd($exp, "sho mem");
cmd($exp, "exit"); # enable
cmd($exp, "exit");
$exp->soft_close;