private function executeUptimeCommand()
    {
        $error = exec($this->resource->command, $system_string, $output);

        if ($output !== 0) {
            throw new DomainException((string) $error);
        }

        return (! is_array($system_string) || empty($system_string))
            ? ''
            : $system_string[0];
    }
private function executeUptimeCommand()
    {
        $error = exec($this->resource->command, $system_string, $output);

        if ($output !== 0) {
            throw new DomainException((string) $error);
        }

        return (! is_array($system_string) || empty($system_string))
            ? ''
            : $system_string[0];
    }
private function executeUptimeCommand ( ) { $ error = exec ( $ this -> resource -> command , $ system_string , $ output ) ; if ( $ output !== 0 ) { throw new DomainException ( ( string ) $ error ) ; } return ( ! is_array ( $ system_string ) || empty ( $ system_string ) ) ? '' : $ system_string [ 0 ] ; }
Execute command to get an uptime string.

@return mixed|string
@throws Exception
Execute command to get an uptime string .