Discovery 1: Get Started with Cisco CLIDiscovery 1：從 Cisco CLI 開始

In this activity, you will learn about EXEC modes, CLI help, and the CLI error message. You will also learn how to manage the Cisco IOS configuration and how to improve user experience in the CLI.

在本活動中，你將學習使用者執行模式與特權執行模式（EXEC modes）、CLI 說明，以及 CLI 錯誤訊息。你也將學習如何管理 Cisco IOS 設定，以及如何改善 CLI 的使用體驗。

Interacting with the device using the CLI is only one of the available options. The other one is using a GUI, when the device's operating system provides one. GUIs may not always provide all features available at the CLI. For these reasons, network devices are typically accessed through a CLI. The CLI is less resource-intensive and very stable when compared to a GUI. However, to use the CLI, the user needs to know the underlying structure that controls the system.

使用 CLI 與裝置互動只是可用選項之一。另一個選項是使用圖形化使用者介面（GUI），前提是裝置的作業系統有提供。GUI 未必總能提供 CLI 可用的所有功能。基於這些原因，網路裝置通常是透過 CLI 存取的。相較於 GUI，CLI 消耗的資源較少，且非常穩定。不過，若要使用 CLI，使用者必須了解控制系統運作的底層架構。

This activity will guide you through the commands that enable you to navigate between user EXEC and privileged EXEC operation modes of the Cisco IOS CLI. Also, it will show you the commands that can assist you when using the CLI.

本活動將帶領你操作可在 Cisco IOS CLI 的使用者執行模式與特權執行模式之間切換的指令。同時也會示範一些能在使用 CLI 時提供協助的指令。

By default, no authentication is required to access the User EXEC Mode from the console. You can enter the User EXEC mode by simply pressing the Enter key. However, if access control (login authentication) is configured, you will be prompted to enter a username and a password before you can continue to the User EXEC Mode. It is a good practice to ensure that authentication is configured during the initial configuration.

根據預設，從主控台存取使用者執行模式不需要任何驗證。你只需按下Enter 鍵即可進入使用者執行模式。不過，若已設定存取控制（登入驗證），系統會先提示你輸入使用者名稱與密碼，才能繼續進入使用者執行模式。建議在初始設定時就設定好驗證，這是良好的做法。

Entering the question mark (?) in the Privileged EXEC Mode reveals many more command options compared to entering the question mark (?) command in the User EXEC Mode. This feature is referred to as context-sensitive help.

在特權執行模式下輸入問號（?），相較於在使用者執行模式下輸入問號（?）指令，會顯示更多的指令選項。這項功能稱為上下文相關說明。

This session will guide you through using the question mark (?) command, which is the command-listing feature of the Cisco IOS CLI. It will also demonstrate how you can take advantage of the tab completion feature of the Cisco IOS CLI. The lab is prepared with the devices represented in the topology, but for this task, you will only use the SW2. You will also examine CLI error messages.

本節將帶領你使用問號（?）指令，這是 Cisco IOS CLI 的指令列表功能。同時也會示範如何運用 Cisco IOS CLI 的Tab 補齊功能。本實驗已備妥拓樸中所呈現的所有裝置，但在本任務中，你只會用到 SW2。你也將檢視 CLI 錯誤訊息。

When you get to know a new program or interface, you usually take advantage of the program's help features. Cisco IOS Software includes extensive command-line help functions, including context-sensitive help. There are two basic types of CLI help features that the Cisco IOS devices provide: context-sensitive help and error message notification. Context-sensitive help offers assistance when you are trying to determine the proper command and syntax. To access it, use the question mark (?) command. For example, you know that the command you would like to use starts with the letters sh, but you are not sure what follows. Enter sh? and the CLI will list all commands that start with sh and that are available in the current operation mode. You can also use the context-sensitive help to figure out the complete syntax for a command.

當你認識一個新程式或介面時，通常會善用該程式的說明功能。Cisco IOS 軟體提供豐富的命令列說明功能，包括上下文相關說明。Cisco IOS 裝置提供兩種基本的 CLI 說明功能：上下文相關說明與錯誤訊息通知。上下文相關說明可在你試圖判斷正確指令與語法時提供協助。要使用它，請輸入問號（?）指令。舉例來說，假設你知道想使用的指令是以字母 sh 開頭，但不確定後面接什麼。輸入 sh?，CLI 就會列出目前操作模式下所有以 sh 開頭且可用的指令。你也可以利用上下文相關說明來判斷某個指令的完整語法。

Another feature of the context-sensitive help is listing all available commands for the current CLI mode. The listing can be used when you are unsure of the name of a command or you want to see if Cisco IOS Software supports a particular command in a particular mode. To use context-sensitive help in this way, enter the question mark (?) at any prompt.

上下文相關說明的另一項功能，是列出目前 CLI 模式下所有可用的指令。當你不確定某個指令名稱，或想確認 Cisco IOS 軟體在特定模式下是否支援某個指令時，可以使用這項列表功能。要以這種方式使用上下文相關說明，只需在任何提示字元下輸入問號（?）。

The second type of CLI help feature is the error message notification. When you enter a command in the CLI, before executing it, its syntax is checked. If the command syntax is not correct, you will be notified of an error that reads, "Invalid input detected at '^' marker." In addition to the text message, the caret symbol (^) will display under the command you typed in, exactly below the place in the command at which the first error is detected. Basically, Cisco IOS Software is saying, "I understood what you typed up to this point."

第二種 CLI 說明功能是錯誤訊息通知。當你在 CLI 中輸入指令後，系統會在執行前先檢查其語法。若指令語法不正確，你會收到錯誤通知，內容為「Invalid input detected at '^' marker.」。除了文字訊息外，插入符號（^）還會顯示在你所輸入指令的下方，精確標示出第一個偵測到錯誤之處的正下方位置。基本上，Cisco IOS 軟體是在說：「我理解你輸入的內容，一直到這個位置為止。」

You may also receive an error message about an ambiguous command. This type of error occurs when you type in the abbreviated version of the command, but the abbreviation matches multiple commands. In Cisco IOS Software, when you type enough letters to match exactly one command, you may press the Enter key, without completing the command. Because there is no other command that starts with these letters, Cisco IOS Software will know exactly which command you had in mind and will execute the command. For example, there are multiple commands that start with the letter "c," but only one command that begins with "clo." If you press Enter after entering only c, you receive an "ambiguous command" error message. On the other hand, if you enter clo and press Enter, you do not receive a message that the command is ambiguous because there is only the clock command that starts with "clo." Although, you would receive an "Incomplete command" error message because the clock does not complete the command. The "Incomplete command" message indicates that you did not enter all elements required by the command syntax and that Cisco IOS Software does not have enough information to interpret what you were requesting.

你也可能收到關於模糊指令的錯誤訊息。當你輸入指令的縮寫版本，但該縮寫同時符合多個指令時，就會發生這類錯誤。在 Cisco IOS 軟體中，當你輸入足夠的字母以唯一對應到一個指令時，即可按下Enter 鍵，而不必輸入完整指令。由於沒有其他指令以這些字母開頭，Cisco IOS 軟體就能準確判斷你所指的是哪個指令並加以執行。舉例來說，有多個指令以字母「c」開頭，但只有一個指令以「clo」開頭。如果你只輸入 c 後就按下Enter，會收到「ambiguous command」（模糊指令）錯誤訊息。反之，若你輸入 clo 後按下Enter，則不會收到模糊指令的訊息，因為只有 clock 這個指令以「clo」開頭。不過，你會收到「Incomplete command」（不完整指令）錯誤訊息，因為單靠 clock 並不能構成完整指令。「Incomplete command」訊息表示你尚未輸入該指令語法所要求的全部元素，Cisco IOS 軟體沒有足夠資訊來解讀你的要求。

The following is an overview of CLI error messages and their interpretations. If you access the SW1 console and use the enable command to access the Privileged EXEC Mode, you can try the following examples as you go along.

以下是 CLI 錯誤訊息及其解讀方式的概覽。如果你存取 SW1 主控台並使用 enable 指令進入特權執行模式，就可以照著以下範例逐步嘗試。

You did not enter enough characters.

你輸入的字元不夠多。

Required arguments or keywords were omitted at the end of the command.

指令結尾缺少必要的引數或關鍵字。

The caret (^) indicates the first element in the command CLI cannot interpret.

插入符號（^）標示出 CLI 無法解讀的指令中的第一個元素。

Use the ? command to follow the correct syntax and set the system clock.

使用 ? 指令依循正確語法，並設定系統時鐘。

You can use context-sensitive help to determine the syntax of a particular command. For example, if the device clock needs to be set, but you are unsure of the clock command syntax, the context-sensitive help provides a means to check the syntax.

你可以使用上下文相關說明來判斷特定指令的語法。舉例來說，若需要設定裝置時鐘，但不確定 clock 指令的語法，上下文相關說明就能提供檢查語法的方式。

Context-sensitive help supplies the entire command even if you enter just the first characters of the command, such as cl?.

即使你只輸入指令的前幾個字元，例如 cl?，上下文相關說明也會顯示完整的指令。

If you enter the command clock but an error message is displayed, indicating that the command is incomplete, enter the ? command (preceded by a space) to determine which arguments are required for the command. In the clock ? example, the help output shows that the keyword set is required after clock.

如果你輸入 clock 指令，卻出現錯誤訊息，指出指令不完整，請輸入 ? 指令（前面加一個空格），以判斷該指令需要哪些引數。在 clock ? 範例中，說明輸出顯示 clock 之後需要 set 這個關鍵字。

If you enter the command clock set but another error message appears, indicating that the command is still incomplete, press the Up Arrow key to repeat the command entry. Then add a space and enter the question mark (?) to display a list of arguments that you can use for the command.

如果你輸入指令 clock set，卻出現另一則錯誤訊息，指出指令仍不完整，請按上方向鍵以重新叫出該指令。接著加一個空格並輸入問號（?），即可顯示可搭配該指令使用的引數清單。

After the last command recall, the example shows that the administrator used the ? to reveal additional arguments, which involve entering the current time using the correct format for the day, month, and year.

在上次叫出指令後，範例顯示管理員使用了 ? 來顯示更多引數，這些引數需要以正確格式輸入當前日、月、年的時間。

The example continues to illustrate how to set the device clock.

範例接著示範如何設定裝置時鐘。

If after entering the current time you still see the Cisco IOS Software error message indicating that the command that you have entered is incomplete, recall the command, add a space, and enter the ? command to display a list of arguments that are available. In this example, enter the day, month, and year using the correct format. Then press Enter to execute the command.

如果輸入目前時間後，仍看到 Cisco IOS 軟體顯示指令不完整的錯誤訊息，請叫出該指令，加一個空格，並輸入 ? 指令以顯示可用的引數清單。在此範例中，請以正確格式輸入日、月、年，然後按Enter 執行該指令。

Syntax checking uses the caret symbol (^) as an error-location indicator. It appears at the command string where the user has first entered an incorrect command, keyword, or argument. The error-location indicator and interactive help system provide a way to find and correct syntax errors easily. In the clock example, the caret symbol indicates that the month was entered incorrectly as a number. The parser is expecting the month to be spelled out.

語法檢查使用插入符號（^）作為錯誤位置指標。它會出現在指令字串中使用者第一次輸入錯誤指令、關鍵字或引數的位置。錯誤位置指標與互動式說明系統提供了一種能輕鬆找出並修正語法錯誤的方式。在 clock 範例中，插入符號指出「月」被誤輸入為數字。剖析器預期「月」應以英文拼寫方式輸入。

Now you will examine the startup and running configurations of a Cisco IOS device. The lab is prepared with the devices that are represented in the topology, but for this task, you will only use SW2. In the end, you will erase the configuration of SW2. The lab system will be correctly configured the next time you initialize the lab.

現在你將檢視 Cisco IOS 裝置的啟動設定與執行中設定。本實驗已備妥拓樸中所呈現的裝置，但在本任務中，你只會用到 SW2。最後，你會清除 SW2 的設定。下次重新初始化實驗時，實驗系統會恢復正確的設定。

When you first access a device for the first time, the prompt includes the hostname that is already configured on the device. You will modify the hostname configuration parameter on the switch as you experiment with the startup and running configurations.

當你第一次存取裝置時，提示字元會顯示裝置上已設定好的主機名稱。在你嘗試操作啟動設定與執行中設定的過程中，你將修改交換器上的主機名稱設定參數。

When a switch or a router starts, it looks for a configuration file in the NVRAM of the device. NVRAM is the memory component in the device hardware that retains stored information (for example, it is nonvolatile) even after the device is powered down. The configuration file that is stored in the NVRAM is called the startup-config file. If there is no startup-config file in NVRAM, which is the case when you buy new equipment, the router or switch enters the setup utility and loads a default configuration. The setup utility also prompts you for specific configuration information to create a basic configuration for the device. You can also interrupt the setup utility and start configuring the device manually on your own.

交換器或路由器啟動時，會在裝置的 NVRAM 中尋找設定檔。NVRAM 是裝置硬體中的一個記憶體元件，即使裝置斷電後（也就是非揮發性），仍會保留所儲存的資訊。儲存在 NVRAM 中的設定檔稱為啟動設定（startup-config）檔。若 NVRAM 中沒有啟動設定檔案，例如購買全新設備時，路由器或交換器就會進入設定精靈，並載入預設設定。設定精靈也會提示你輸入特定的設定資訊，以便為裝置建立基本設定。你也可以中斷設定精靈，自行手動開始設定裝置。

Once the device has started, the system copies the startup configuration to RAM. The configuration file in RAM is called the running-config file. As you make configuration changes, the system stores them in the running configuration. It is important to understand that RAM does not retain stored information when the device is powered off or rebooted. If a change is made to the running configuration, it should be copied to the nonvolatile memory to be retained after a reboot. One way you can do that is to use the copy running-config startup-config command to store the changes in the startup-config file in the NVRAM.

裝置啟動後，系統會將啟動設定複製到 RAM。RAM 中的設定檔稱為執行中設定（running-config）檔。當你進行設定變更時，系統會將這些變更儲存到執行中設定裡。務必了解，裝置斷電或重新開機時，RAM 並不會保留所儲存的資訊。若你對執行中設定做了變更，就應將其複製到非揮發性記憶體，才能在重新開機後保留下來。其中一種方式，是使用 copy running-config startup-config 指令，將變更儲存到 NVRAM 中的啟動設定檔案。

In addition to NVRAM and RAM, Cisco devices have a ROM and flash memory. ROM is a form of permanent storage. This type of memory contains a microcode for basic functions to start and maintain the router. ROM is nonvolatile, so it maintains the memory contents even when the power is turned off.

除了 NVRAM 與 RAM 之外，Cisco 裝置還具有 ROM 與快閃記憶體。ROM 是一種永久儲存裝置。這類記憶體包含用於啟動與維護路由器基本功能的微碼。ROM 是非揮發性的，因此即使斷電，仍會保留記憶體內容。

Flash memory is similar to a hard drive in that the information that the system stores there is retained even when the device is powered off. Cisco IOS Software is stored in flash memory. Flash memory may also store backup configuration files and additional device-related files.

快閃記憶體類似硬碟，系統儲存於其中的資訊即使裝置斷電也會保留。Cisco IOS 軟體就儲存在快閃記憶體中。快閃記憶體也可能儲存備份設定檔以及其他與裝置相關的檔案。

To view the configuration files, use the show command, followed by the name of the file that stores the configuration. For example, if you want to view the running configuration, type show running-config. Remember, running-config is the name of the file that stores the running configuration. For the device to retain the running configuration, store it to NVRAM. You can replace the startup-config file that already resides in NVRAM with the running configuration. Use the copy command, followed by the names of the source and destination files. The complete command is copy running-config startup-config. Review the table for additional commonly used Cisco IOS commands.

若要檢視設定檔案，可使用 show 指令，後面接上儲存該設定的檔案名稱。舉例來說，若要檢視執行中設定，輸入 show running-config。請記住，running-config 是儲存執行中設定的檔案名稱。若要讓裝置保留執行中設定，需將其儲存到 NVRAM。你可以用執行中設定取代已存在於 NVRAM 中的啟動設定檔。使用 copy 指令，後面接上來源與目的檔案的名稱。完整指令為 copy running-config startup-config。請參閱下表以了解其他常用的 Cisco IOS 指令。

You can also use the copy command to copy configuration files and Cisco IOS Software files from a switch or a router to other network locations, such as a server and vice versa, using FTP, Secure Copy Protocol (SCP), HTTP, TFTP, and other protocols.

你也可以使用 copy 指令，透過 FTP、安全複製通訊協定（SCP）、HTTP、TFTP 等通訊協定，將設定檔與 Cisco IOS 軟體檔案從交換器或路由器複製到其他網路位置（例如伺服器），反之亦然。

For example, in the copy running-config tftp: command, the system copies the running configuration in RAM to a TFTP server. To remember the copy command syntax, you might find the mnemonic copy from to useful. To complete copying, you must supply additional network information about the TFTP server—namely, its IP address or name. You must also specify the name of the destination file to which you are copying. During the copying process, a series of exclamation marks show the progress of the upload.

舉例來說，在 copy running-config tftp: 指令中，系統會將 RAM 中的執行中設定複製到 TFTP 伺服器。要記住 copy 指令的語法，你可以善用 copy from to（從……複製到……）這個記憶口訣。要完成複製，你必須提供 TFTP 伺服器的其他網路資訊，也就是其 IP 位址或名稱。你還必須指定要複製到的目的檔案名稱。複製過程中，一連串的驚嘆號會顯示上傳的進度。

Copying configuration files from a switch or a router to a server are useful for backing up the configuration files and for centralizing the file management.

將設定檔從交換器或路由器複製到伺服器，有助於備份設定檔並集中管理檔案。

Copying configuration files from an external server to the running configuration in RAM or to the startup configuration file in NVRAM of the router or switch is useful for restoring backups.

將設定檔從外部伺服器複製到路由器或交換器 RAM 中的執行中設定，或 NVRAM 中的啟動設定檔案，對於還原備份很有幫助。

To create a device configuration backup, you should copy the configuration files to another device, such as a dedicated server.

若要建立裝置設定備份，應將設定檔複製到另一台裝置，例如專用的伺服器。

When you copy a configuration into RAM, regardless of the source, the copied configuration merges with the existing configuration in RAM. It does not overwrite it. New parameters are added, and changes to existing parameters overwrite the old ones. Configuration parameters in RAM for which there is no corresponding parameter in the source file remain unaffected.

當你將設定複製到 RAM 中時，無論來源為何，複製進來的設定都會與 RAM 中既有的設定合併，而不會覆蓋整份設定。新的參數會被新增，而既有參數的變更會覆蓋舊值。至於 RAM 中那些在來源檔案裡沒有對應參數的設定，則不受影響。

In this session, you will practice using terminal history. Recalling recently entered commands is useful because it reduces typing. Once you recall a command, you can simply press Enter to use the exact same command, or you can modify it. The lab is prepared with the devices that are represented in the topology, but for this session, you will only use R1.

在本節中，你將練習使用終端機歷程。回憶最近輸入過的指令十分有用，因為可以減少打字。叫回一個指令後，你可以直接按Enter 鍵重複執行同一指令，或加以修改。本實驗已備妥拓樸中所呈現的裝置，但在本節中，你只會用到 R1。

The prompt displays the hostname that is configured on the device. You will modify this parameter of the router configuration as you experiment with the startup and running configurations.

提示字元會顯示裝置上已設定的主機名稱。在你嘗試操作啟動設定與執行中設定的過程中，你將修改路由器設定的這項參數。

The Cisco IOS CLI includes many features that make the configuration and verification process easier and faster. These features include command-line editing keys, command history, and filtering parameters.

Cisco IOS CLI 包含許多能讓設定與驗證流程更輕鬆快速的功能，包括命令列編輯按鍵、指令歷程，以及篩選參數。

Command-line editing keys are shortcuts and hotkeys that the CLI provides. Use these shortcuts and hotkeys to move the cursor around on the command line for corrections or changes. Use them also to make configuring, monitoring, and troubleshooting easier. The table describes each of the shortcuts for command-line editing and controlling command entry.

命令列編輯按鍵是 CLI 所提供的捷徑鍵與快速鍵。使用這些捷徑鍵與快速鍵，可在命令列上移動游標以進行修正或變更，也能讓設定、監控與疑難排解變得更輕鬆。下表列出各個用於命令列編輯與控制指令輸入的捷徑鍵。

The Cisco CLI provides a history or record of commands that users have entered. You will find this feature, called the command history, particularly useful when recalling long or complex commands or entries.

Cisco CLI 提供使用者已輸入指令的歷程紀錄。在叫回較長或較複雜的指令或項目時，這項稱為指令歷程的功能將特別實用。

Another useful feature that improves the user experience in the CLI is the filtering of show outputs. Using filtering, you can display only the parts of show outputs that you are interested in. You can filter outputs by typing the pipe (|) character after a show command, followed by a filtering parameter and a filtering expression. The table describes filtering parameters that are available for output filtering. The filtering expression is case-sensitive and must match exactly. For example, it must not have extra spaces.

另一項能改善 CLI 使用體驗的實用功能，是對 show 輸出進行篩選。透過篩選，你可以只顯示 show 輸出中你感興趣的部分。你可以在 show 指令後輸入管線（|）字元，再接上篩選參數與篩選運算式，來篩選輸出結果。下表列出可用於輸出篩選的篩選參數。篩選運算式區分大小寫，且必須完全相符，例如不能有多餘的空格。