Command Line Interface
Negating the Effect of Commands
For many configuration commands you can enter the prefix keyword “no” to cancel the effect of a command or reset the configuration to the default value. For example, the logging command will log system messages to a host server. To disable logging, specify the no logging command. This guide describes the negation effect for all applicable commands.
Using Command History
The CLI maintains a history of commands that have been entered. You can scroll back through the history of commands by pressing the up arrow key. Any command displayed in the history list can be executed again, or first modified and then executed.
Using the show history command displays a longer list of recently executed commands.
Understanding Command Modes
The command set is divided into Exec and Configuration classes. Exec commands generally display information on system status or clear statistical counters. Configuration commands, on the other hand, modify interface parameters or enable certain functions. These classes are further divided into different modes. Available commands depend on the selected mode. You can always enter a question mark “?” at the prompt to display a list of the commands available for the current mode. The command classes and associated modes are displayed in the following table:
Class | Mode |
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Exec | Privileged |
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Configuration | Global |
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