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Catalyst 2900 Series XL and Catalyst 3500 Series XL Software Configuration Guide
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Chapter 3 Getting Started with the CLI
Command Usage Basics
Using the No and Default Forms of Commands
Almost every configuration command has a no form. In general, use the no form to
•
Disable a feature or function.
•
Reset a command to its default values.
•
Reverse the action of a command. For example, the no shutdown command reverses the shutdown
of an interface.
Use the command without the no form to reenable a disabled feature or to reverse the action of a no
command.
Configuration commands can also have a default form. The default form of a command returns the
command setting to its default. Most commands are disabled by default, so the default form is the same
as the no form. However, some commands are enabled by default and have variables set to certain default
values. In these cases, the default command enables the command and sets variables to their default
values.
Redisplaying a Command
To redisplay a command you previously entered, press the up-arrow key. You can continue to press the
up-arrow key for more commands.
Getting Help
Entering a question mark (?) at the system prompt displays a list of commands for each command mode.
When using context-sensitive help, the space (or lack of a space) before the question mark (?) is
significant. To obtain a list of commands that begin with a particular character sequence, enter those
characters followed immediately by the question mark (?). Do not include a space. This form of help is
called word help, because it completes a word for you.
To list keywords or arguments, enter a question mark (?) in place of a keyword or argument. Include a
space before the ?. This form of help is called command syntax help, because it reminds you which
keywords or arguments are applicable based on the command, keywords, and arguments you already
have entered.
