Command-Line Interfaces

This chapter describes the CLIs you use to configure the Catalyst 4500 series switch. This chapter includes the following major sections:

•Accessing the Switch CLI

•Performing Command-Line Processing

•Performing History Substitution

•Understanding Cisco IOS Command Modes

•Getting a List of Commands and Syntax

•ROMMON Command-Line Interface

Note For complete syntax and usage information for the switch commands used in this chapter, look at the Cisco Catalyst 4500 Series Switch Command Reference and related publications at this location:

http://www.cisco.com/en/US/products/hw/switches/ps4324/index.html

If the command is not found in the Catalyst 4500 Command Reference, it is located in the larger Cisco IOS library. Refer to the Catalyst 4500 Series Switch Cisco IOS Command Reference and related publications at this location:

http://www.cisco.com/en/US/products/ps6350/index.html

Accessing the Switch CLI

The following sections describe how to access the switch CLI:

•Accessing the CLI Using the EIA/TIA-232 Console Interface

•Accessing the CLI Through Telnet

Accessing the CLI Using the EIA/TIA-232 Console Interface

Note EIA/TIA-232 was known as recommended standard 232 (RS-232) before its acceptance as a standard by the Electronic Industries Alliance (EIA) and Telecommunications Industry Association (TIA).

Perform the initial switch configuration over a connection to the EIA/TIA-232 console interface. Refer to the Catalyst 4500 Series Switch Module Installation Guide for console interface cable connection procedures.

To access the switch through the console interface, perform this task:

 
Command
Purpose

Step 1 

Switch> enable

From the user EXEC prompt (>), enter enable to change to enable mode (also known as privileged mode or privileged EXEC mode).

Step 2 

Password: password


Switch#

At the password prompt, enter the system password. The prompt (#) appears, indicating that you have accessed the CLI in enabled mode.

Step 3 

Switch# quit

When you are finished executing the task command, exit the session.

After accessing the switch through the EIA/TIA-232 interface, you see this display: 

Press Return for Console prompt


Switch> enable

Password:< >

Switch#

Accessing the CLI Through Telnet

Note Before you make a Telnet connection to the switch, you must set the IP address for the switch. See the "Configuring Physical Layer 3 Interfaces" section on page 25-4.

The switch supports up to eight simultaneous Telnet sessions. Telnet sessions disconnect automatically after remaining idle for the period specified by the exec-timeout command.

To make a Telnet connection to the switch, perform this task:

 
Command
Purpose

Step 1 

telnet {hostname | ip_addr}

From the remote host, enter the telnet command and the name or IP address of the switch you want to access.

Step 2 

Password: password


Switch#

At the prompt, enter the password for the CLI. If no password has been configured, press Return.

Step 3 


Enter the necessary commands to complete your desired tasks.

Step 4 

Switch# quit

When finished, exit the Telnet session.

This example shows how to open a Telnet session to the switch: 

unix_host% telnet Switch_1

Trying 172.20.52.40...

Connected to 172.20.52.40.

Escape character is '^]'.

User Access Verification

Password:< >

Switch_1> enable

Password:

Switch_1#

Performing Command-Line Processing

Switch commands are not case sensitive. You can abbreviate commands and parameters if the abbreviations contain enough letters to be different from any other currently available commands or parameters.

You can scroll through the last 20 commands stored in the history buffer and enter or edit a command at the prompt. Table 2-1 lists the keyboard shortcuts for entering and editing switch commands.

Table 2-1 Keyboard Shortcuts

Keystrokes
Result

Press Ctrl-B or
press the Left Arrow key1

Moves the cursor back one character.

Press Ctrl-F or
press the Right Arrow key1

Moves the cursor forward one character.

Press Ctrl-A

Moves the cursor to the beginning of the command line.

Press Ctrl-E

Moves the cursor to the end of the command line.

Press Esc-B

Moves the cursor back one word.

Press Esc-F

Moves the cursor forward one word.

1 The Arrow keys function only on ANSI-compatible terminals, such as VT100s.


Performing History Substitution

The history buffer stores the last 20 command lines you entered. History substitution enables you to access these command lines without retyping them. Table 2-2 lists the history substitution commands.

Table 2-2 History Substitution Commands 

Command
Purpose

Ctrl-P or the Up Arrow key1

Recalls commands in the history buffer, beginning with the most recent command. Repeat the key sequence to recall older commands successively.

Ctrl-N or the Down Arrow key1

Returns to more recent commands in the history buffer after commands have been recalled with Ctrl-P or the Up Arrow key. Repeat the key sequence to recall more recent commands.

Switch# show history

Lists the last several commands you have entered in EXEC mode.

1 The Arrow keys function only on ANSI-compatible terminals such as VT100s.


Understanding Cisco IOS Command Modes

Note For complete information about Cisco IOS command modes, refer to the Cisco IOS Configuration Fundamentals Configuration Guide and the Cisco IOS Configuration Fundamentals Command Reference at: http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/index.htm

The Cisco IOS user interface has many different modes: user EXEC, privileged EXEC (enable), global configuration, interface, subinterface, and protocol-specific. The commands available to you depend on which mode you are in. To get a list of the commands in a given mode, enter a question mark (?) at the system prompt. See the "Getting a List of Commands and Syntax" section for more information.

When you start a session on the switch, you begin in user mode, also called user EXEC mode. Only a small subset of commands are available in EXEC mode. To have access to all commands, you must enter privileged EXEC mode, also called enable mode. To access the privileged EXEC mode, you must enter a password. When you are in the privileged EXEC mode, you can enter any EXEC command or access global configuration mode. Most EXEC commands are one-time commands, such as show commands, which display the current configuration status, and clear commands, which reset counters or interfaces. The EXEC commands are not saved when the switch is rebooted.

The configuration modes allow you to make changes to the running configuration. If you save the configuration, these commands are stored when you reboot the switch. You must start in global configuration mode. From global configuration mode, you can enter interface configuration mode, subinterface configuration mode, and a variety of protocol-specific modes.

You would use a separate mode called ROMMON when the switch cannot boot up properly. For example, the switch might enter ROMMON mode if it does not find a valid system image when it is booting, or if its configuration file is corrupted. For more information, see the "ROMMON Command-Line Interface" section.

Table 2-3 lists and describes frequently used Cisco IOS modes.

Table 2-3 Frequently Used Cisco IOS Command Modes 

Mode
What You Use It For
How to Access
Prompt

User EXEC

To connect to remote devices, change terminal settings on a temporary basis, perform basic tests, and display system information.

Log in.

Switch>

Privileged EXEC (enable)

To set operating parameters. The privileged command set includes the commands in user EXEC mode, as well as the configure command. Use the configure command to access the other command modes.

From user EXEC mode, enter the enable command and the enable password (if a password has been configured).

Switch#

Global configuration

To configure features that affect the system as a whole, such as the system time or switch name.

From privileged EXEC mode, enter the configure terminal command.

Switch(config)#

Interface configuration

To enable or modify the operation of a 10-Gigabit Ethernet, Gigabit Ethernet, or Fast Ethernet interface with interface commands.

From global configuration mode, enter the interface type location command.

Switch(config-if)#

Console configuration

To configure the console interface; from the directly connected console or the virtual terminal; used with Telnet.

From global configuration mode, enter the line console 0 command.

Switch(config-line)#


The Cisco IOS command interpreter, called the EXEC, interprets and runs the commands you enter. You can abbreviate commands and keywords by entering just enough characters to make the command unique from other commands. For example, you can abbreviate the show command to sh and the configure terminal command to config t.

When you type exit, the switch backs out one level. To exit configuration mode completely and return to privileged EXEC mode, press Ctrl-Z.

Getting a List of Commands and Syntax

In any command mode, you can get a list of available commands by entering a question mark (?). 

Switch> ?

To obtain a list of commands that begin with a particular character sequence, enter those characters followed by the question mark (?). Do not include a space before the question mark. 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 question mark. 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 have already entered. 

Switch# configure ?

  memory             Configure from NV memory

  network            Configure from a TFTP network host

  overwrite-network  Overwrite NV memory from TFTP network host

  terminal           Configure from the terminal

  <cr>

To redisplay a command you previously entered, press the Up Arrow key or Ctrl-P. You can continue to press the Up Arrow key to see the last 20 commands you entered.

Tip If you are having trouble entering a command, check the system prompt and enter the question mark (?) for a list of available commands. You might be in the wrong command mode or using incorrect syntax.

Type exit to return to the previous mode. Press Ctrl-Z or enter the end command in any mode to immediately return to privileged EXEC mode.

Virtual Console for Standby Supervisor Engine

Catalyst 4500 series switches can be configured with 2 supervisor engines to provide redundancy. When the switch is powered, one of the supervisor engines becomes active and remains active until a switchover occurs. The other supervisor engine remains in standby mode.

Each supervisor engine has its own console port. Access to the standby supervisor engine is possible only through the console port of the standby supervisor engine. Therefore, you must connect to the standby console to access, monitor or debug the standby supervisor.

Virtual Console for Standby Supervisor Engine enables you to access the standby console from the active supervisor engine without requiring a physical connection to the standby console. It uses IPC over EOBC to communicate with the standby supervisor engine and thus emulate the standby console on the active supervisor engine. Only one active standby console session is active at any time.

The Virtual Console for Standby Supervisor Engine enables users who are logged onto the active supervisor engine to remotely execute show commands on the standby supervisor engine and view the results on the active supervisor engine. Virtual Console is available only from the active supervisor engine.

You can access the standby virtual console from the active supervisor engine with the attach module, session module, or remote login commands on the active supervisor engine. You must be in privilege EXEC mode (level 15) to run these commands to access the standby console.

Once you enter the standby virtual console, the terminal prompt automatically changes to "<hostname>-standby-console#" where hostname is the configured name of the switch. The prompt is restored back to the original prompt when you exit the virtual console.

You exit the virtual console with the exit or quit commands. When the inactivity period of the terminal on the active supervisor engine where you logged in exceeds the configured idle time, you are automatically logged out of the terminal on the active supervisor engine. In such a case, the virtual console session is also terminated. Virtual console session is also automatically terminated when the standby is rebooted. After the standby boots up, you need to create another virtual console session.

To login to the standby supervisor engine using a virtual console, do the following: 

Switch# session module 2

Connecting to standby virtual console

Type "exit" or "quit" to end this session


Switch-standby-console# exit

Switch#

If the standby console is not enabled, the following message appears. 

Switch-standby-console#

Standby console disabled.

Valid commands are: exit, logout

Note The standby virtual console provides the standard features that are available from the supervisor console such as command history, command completion, command help and partial command keywords.

The following limitations apply to the standby virtual console:

•All commands on the virtual console run to completion. It does not provide the auto-more feature; it behaves as if the terminal length 0 command has been executed. It is also non-interactive. Therefore, a running command cannot be interrupted or aborted by any key sequence on the active supervisor engine. Therefore if a command produces considerable output, the virtual console displays it on the supervisor screen.

•The virtual console is non-interactive. Because the virtual console does not detect the interactive nature of a command, any command that requires user interaction causes the virtual console to wait until the RPC timer aborts the command.

The virtual console timer is set to 60 seconds. The virtual console returns to its prompt after 60 seconds. During this time, you cannot abort the command from the key board. You must wait for the timer to expire before you continue.

•You cannot use virtual console to view debug and syslog messages that are being displayed on the standby supervisor engine. The virtual console only displays the output of commands that are executed from the virtual console. Other information that is displayed on the real standby console does not appear on the virtual console.

ROMMON Command-Line Interface

ROMMON is a ROM-based program that is involved at power-up or reset, or when a fatal exception error occurs. The switch enters ROMMON mode provided one of the following occurs:

•The switch does not find a valid software image.

•The NVRAM configuration is corrupted.

•The configuration register is set to enter ROMMON mode.

From ROMMON mode, you can load a software image manually from Flash memory, from a network server file, or from bootflash.

The switch also enters ROMMON mode when you restart the switch or when you press Ctrl-C during the first five seconds of startup.

Note Ctrl-C is always enabled for 60 seconds after you reboot the switch, even if Ctrl-C is configured to be off in the configuration register settings.

When you enter ROMMON mode, the prompt changes to rommon 1>. Use the ? command to see the available ROMMON commands.

For more information on ROMMON, see Chapter 49, "ROM Monitor".

For information on the ROMMON commands, refer to the Catalyst 4500 Series Switch Cisco IOS Command Reference and related publications at this location:

http://www.cisco.com/univercd/cc/td/doc/product/software/ios123/123cgcr/index.htm