No and Default Forms of Commands
Almost every configuration command also has a
no
form. In general, use the
no
form to disable a feature or
function or reverse the action of a command. For example, the
no shutdown
interface configuration command
reverses the shutdown of an interface. Use the command without the keyword
no
to reenable a disabled feature
or to enable a feature that is disabled by default.
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.
CLI Error Messages
This table lists some error messages that you might encounter while using the CLI to configure your device.
Table 2: Common CLI Error Messages
How to Get Help
Meaning
Error Message
Reenter the command followed by
a question mark (?) without any
space between the command and
the question mark.
The possible keywords that you can
enter with the command appear.
You did not enter enough
characters for your device to
recognize the command.
% Ambiguous command: "show
con"
Reenter the command followed by
a question mark (?) with a space
between the command and the
question mark.
The possible keywords that you can
enter with the command appear.
You did not enter all of the
keywords or values required by this
command.
% Incomplete command.
Enter a question mark (?) to display
all of the commands that are
available in this command mode.
The possible keywords that you can
enter with the command appear.
You entered the command
incorrectly. The caret (^) marks the
point of the error.
% Invalid input detected at
‘
^
’
marker.
Configuration Logging
You can log and view changes to the device configuration. You can use the Configuration Change Logging
and Notification feature to track changes on a per-session and per-user basis. The logger tracks each
configuration command that is applied, the user who entered the command, the time that the command was
entered, and the parser return code for the command. This feature includes a mechanism for asynchronous
IP Multicast Routing Configuration Guide, Cisco IOS XE Release 3SE (Catalyst 3650 Switches)
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Using the Command-Line Interface
No and Default Forms of Commands
