private function hasSttyAvailable(): bool
    {
        if (null !== self::$stty) {
            return self::$stty;
        }

        exec('stty 2>&1', $output, $exitcode);

        return self::$stty = 0 === $exitcode;
    }
private function hasSttyAvailable(): bool
    {
        if (null !== self::$stty) {
            return self::$stty;
        }

        exec('stty 2>&1', $output, $exitcode);

        return self::$stty = 0 === $exitcode;
    }
private function hasSttyAvailable ( ) : bool { if ( null !== self :: $ stty ) { return self :: $ stty ; } exec ( 'stty 2>&1' , $ output , $ exitcode ) ; return self :: $ stty = 0 === $ exitcode ; }
Returns whether Stty is available or not.
Returns whether Stty is available or not .