Pimcore\Config::locateConfigFile PHP Method

    public static function locateConfigFile($name)
    {
        if (!isset(self::$configFileCache[$name])) {
            $pathsToCheck = [PIMCORE_CUSTOM_CONFIGURATION_DIRECTORY, PIMCORE_CONFIGURATION_DIRECTORY];
            $file = null;
            // check for environment configuration
            $env = self::getEnvironment();
            if ($env) {
                $fileExt = File::getFileExtension($name);
                $pureName = str_replace("." . $fileExt, "", $name);
                foreach ($pathsToCheck as $path) {
                    $tmpFile = $path . "/" . $pureName . "." . $env . "." . $fileExt;
                    if (file_exists($tmpFile)) {
                        $file = $tmpFile;
                        break;
                    }
                }
            }
            //check for config file without environment configuration
            if (!$file) {
                foreach ($pathsToCheck as $path) {
                    $tmpFile = $path . "/" . $name;
                    if (file_exists($tmpFile)) {
                        $file = $tmpFile;
                        break;
                    }
                }
            }
            //get default path in pimcore configuration directory
            if (!$file) {
                $file = PIMCORE_CONFIGURATION_DIRECTORY . "/" . $name;
            }
            self::$configFileCache[$name] = $file;
        }
        return self::$configFileCache[$name];
    }

 /**
  * @param array $config
  */
 public function config($config = [])
 {
     $settings = null;
     // check for an initial configuration template
     // used eg. by the demo installer
     $configTemplatePath = PIMCORE_CONFIGURATION_DIRECTORY . "/system.template.php";
     if (file_exists($configTemplatePath)) {
         try {
             $configTemplate = new \Zend_Config(include $configTemplatePath);
             if ($configTemplate->general) {
                 // check if the template contains a valid configuration
                 $settings = $configTemplate->toArray();
                 // unset database configuration
                 unset($settings["database"]["params"]["host"]);
                 unset($settings["database"]["params"]["port"]);
             }
         } catch (\Exception $e) {
         }
     }
     // set default configuration if no template is present
     if (!$settings) {
         // write configuration file
         $settings = ["general" => ["timezone" => "Europe/Berlin", "language" => "en", "validLanguages" => "en", "debug" => "1", "debugloglevel" => "debug", "custom_php_logfile" => "1", "extjs6" => "1"], "database" => ["adapter" => "Mysqli", "params" => ["username" => "root", "password" => "", "dbname" => ""]], "documents" => ["versions" => ["steps" => "10"], "default_controller" => "default", "default_action" => "default", "error_pages" => ["default" => "/"], "createredirectwhenmoved" => "", "allowtrailingslash" => "no", "generatepreview" => "1"], "objects" => ["versions" => ["steps" => "10"]], "assets" => ["versions" => ["steps" => "10"]], "services" => [], "cache" => ["excludeCookie" => ""], "httpclient" => ["adapter" => "Zend_Http_Client_Adapter_Socket"]];
     }
     $settings = array_replace_recursive($settings, $config);
     // create initial /website/var folder structure
     // @TODO: should use values out of startup.php (Constants)
     $varFolders = ["areas", "assets", "backup", "cache", "classes", "config", "email", "log", "plugins", "recyclebin", "search", "system", "tmp", "versions", "webdav"];
     foreach ($varFolders as $folder) {
         \Pimcore\File::mkdir(PIMCORE_WEBSITE_VAR . "/" . $folder);
     }
     $configFile = \Pimcore\Config::locateConfigFile("system.php");
     File::putPhpFile($configFile, to_php_data_file_format($settings));
 }