sub work ()
{
    my $err_flg = 0;
 
    $exp->send("command\r");
    $exp->expect(5,
        [ qr/ERROR MESSAGE 1/i, sub { my $self = shift;
            sleep(1);
            $err_flg = 1; }],
        [ qr/ERROR MESSAGE 2/i, sub { my $self = shift;
            sleep(1);
            $err_flg = 1; }],
        [ qr/command prompt/i, sub { my $self = shift;
            sleep(1);
            $self->send("command\r"); }]
    ) or return(1);
    if ($err_flg == 1)
    {
        return(1);
    }
 
    return(0);
}