Command Line Interface
6-6Negating 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
Exec Privileged
Configuration Global
Interface-ethernet
Interface-wireless