## 型別和驗證

這些環境變數只能處理**文字字串**，因為它們是位於 Python 範疇之外的，必須與其他程式和作業系統的其餘部分相容（甚至與不同的作業系統相容，如 Linux、Windows、macOS）。

這意味著從環境變數中讀取的**任何值**在 Python 中都將是一個 `str`，任何型別轉換或驗證都必須在程式碼中完成。

你將在[進階使用者指南 - 設定和環境變數](./advanced/settings.md)中了解更多關於使用環境變數處理**應用程式設定**的資訊。

## `PATH` 環境變數

有一個**特殊的**環境變數稱為 **`PATH`**，作業系統（Linux、macOS、Windows）用它來查找要執行的程式。

`PATH` 變數的值是一個長字串，由 Linux 和 macOS 上的冒號 `:` 分隔的目錄組成，而在 Windows 上則是由分號 `;` 分隔的。

            this.inputLocation = inputLocation;
            return this;
        }

        /**
         * Builds a new XmlNode instance with the current builder settings.
         *
         * @return a new immutable XmlNode instance
         * @throws NullPointerException if name has not been set
         */
        public XmlNode build() {

    /**
     * Initializes the crawler statistics helper.
     * Sets up the statistics logger and creates the cache for storing
     * statistics objects with the configured size and expiration settings.
     */
    @PostConstruct
    public void init() {
        statsLogger = LogManager.getLogger(loggerName);
        statsCache = CacheBuilder.newBuilder()
                .maximumSize(maxCacheSize)

            // In a real implementation, this should be passed from the session context
            jcifs.CIFSContext context = createDefaultContext();

            // Create transport with multi-channel specific settings
            // Multi-channel transports should use signing consistently with the main session
            boolean forceSigning = context.getConfig().isSigningEnforced();

	CheckPrecondFn      CheckPreconditionFn // only set during GetObject/HeadObject/CopyObjectPart preconditional valuation
	EvalMetadataFn      EvalMetadataFn      // only set for retention settings, meant to be used only when updating metadata in-place.
	DeleteReplication   ReplicationState    // Represents internal replication state needed for Delete replication
	Transition          TransitionOptions

Bạn sẽ học thêm về việc sử dụng biến môi trường để xử lí **các thiết lập ứng dụng** trong [Hướng dẫn nâng cao - Các thiết lập và biến môi trường](./advanced/settings.md){.internal-link target=_blank}.

## Biến môi trường `PATH`

Có một biến môi trường **đặc biệt** được gọi là **`PATH`** được sử dụng bởi các hệ điều hành (Linux, macOS, Windows) nhằm tìm các chương trình để thực thi.

		writeErrorResponseJSON(ctx, w, toAdminAPIErr(ctx, err), r.URL)
		return
	}
}

// RestoreConfigHistoryKVHandler - restores a config with KV settings for the given KV id.
func (a adminAPIHandlers) RestoreConfigHistoryKVHandler(w http.ResponseWriter, r *http.Request) {
	ctx := r.Context()

	objectAPI, _ := validateAdminReq(ctx, w, r, policy.ConfigUpdateAdminAction)

 *
 * <p>The parser handles the following GSA configuration elements:
 * <ul>
 * <li>Collections with good/bad URL patterns</li>
 * <li>Global parameters including start URLs and filtering rules</li>
 * <li>User agent settings</li>
 * <li>URL pattern matching with regular expressions and contains filters</li>
 * </ul>
 *
 */
public class GsaConfigParser extends DefaultHandler {

    /** Logger instance for this class. */

```
sudo pip install yq
alias kv-pairify='yq ".configuration[]" | jq ".[]" | jq -r ".name + \"=\" + .value"'
```

Let's take for example a set of 12 compute nodes with an aggregate memory of _1.2TiB_, we need to do following settings for optimal results. Add the following optimal entries for _core-site.xml_ to configure _s3a_ with **MinIO**. Most important options here are

```
cat ${HADOOP_CONF_DIR}/core-site.xml | kv-pairify | grep "mapred"

labels.logout=Logout
labels.do_you_want_to_logout=Do you want to logout?
labels.logout_button=Logout
labels.profile=Change Password
labels.administration=Administration
labels.profile_button=Settings
labels.profile.title=Settings
labels.profile.update=Update
labels.profile.back=Back
labels.profile.placeholder_old_password=Current Password
labels.profile.placeholder_new_password=New Password