Cisco Systems 3750E manual Using the Command-Line Interface, Understanding Command Modes

C H A P T E R 2

Using the Command-Line Interface

This chapter describes the Cisco IOS command-line interface (CLI) and how to use it to configure your standalone Catalyst 3750-E or 3560-E switch and to a Catalyst 3750-E switch stack, referred to as the switch. It contains these sections:

•Understanding Command Modes, page 2-1

•Understanding the Help System, page 2-3

•Understanding Abbreviated Commands, page 2-4

•Understanding no and default Forms of Commands, page 2-4

•Understanding CLI Error Messages, page 2-5

•Using Configuration Logging, page 2-5

•Using Command History, page 2-6

•Using Editing Features, page 2-7

•Searching and Filtering Output of show and more Commands, page 2-10

•Accessing the CLI, page 2-10

Understanding Command Modes

The Cisco IOS user interface is divided into many different modes. The commands available to you depend on which mode you are currently in. Enter a question mark (?) at the system prompt to obtain a list of commands available for each command mode.

When you start a session on the switch, you begin in user mode, often called user EXEC mode. Only a limited subset of the commands are available in user EXEC mode. For example, most of the user EXEC commands are one-time commands, such as show commands, which show the current configuration status, and clear commands, which clear counters or interfaces. The user EXEC commands are not saved when the switch reboots.

To have access to all commands, you must enter privileged EXEC mode. Normally, you must enter a password to enter privileged EXEC mode. From this mode, you can enter any privileged EXEC command or enter global configuration mode.

Using the configuration modes (global, interface, and line), you can make changes to the running configuration. If you save the configuration, these commands are stored and used when the switch reboots. To access the various configuration modes, you must start at global configuration mode. From global configuration mode, you can enter interface configuration mode and line configuration mode.

Catalyst 3750-E and 3560-E Switch Software Configuration Guide

OL-9775-02 2-1