How to set the exit status code in a Symfony2 command?

In the base Command class:

    if ($this->code) {
        $statusCode = call_user_func($this->code, $input, $output);
    } else {
        $statusCode = $this->execute($input, $output);
    }

    return is_numeric($statusCode) ? (int) $statusCode : 0;

So simply return the exit code from your execute() function. Your console command will exit with this code as long as it is a numeric value.