The documentation set for this product strives to use bias-free language. For the purposes of this documentation set, bias-free is defined as language that does not imply discrimination based on age, disability, gender, racial identity, ethnic identity, sexual orientation, socioeconomic status, and intersectionality. Exceptions may be present in the documentation due to language that is hardcoded in the user interfaces of the product software, language used based on RFP documentation, or language that is used by a referenced third-party product. Learn more about how Cisco is using Inclusive Language.
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.
You can start a CLI session through a console connection, through Telnet, a SSH, or by using the browser.
When you start a session, 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 device 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 device 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.
This table describes the main command modes, how to access each one, the prompt you see in that mode, and how to exit the mode.
Mode |
Access Method |
Prompt |
Exit Method |
About This Mode |
---|---|---|---|---|
User EXEC |
Begin a session using Telnet, SSH, or console. |
Device>
|
Enter logout or quit. |
Use this mode to |
Privileged EXEC |
While in user EXEC mode, enter the enable command. |
Device#
|
Enter disable to exit. |
Use this mode to verify commands that you have entered. Use a password to protect access to this mode. |
Global configuration |
While in privileged EXEC mode, enter the configure command. |
Device(config)#
|
To exit to privileged EXEC mode, enter exit or end, or press Ctrl-Z. |
Use this mode to configure parameters that apply to the entire device. |
VLAN configuration |
While in global configuration mode, enter the vlan vlan-id command. |
Device(config-vlan)#
|
To exit to global configuration mode, enter the exit command. To return to privileged EXEC mode, press Ctrl-Z or enter end. |
Use this mode to configure VLAN parameters. When VTP mode is transparent, you can create extended-range VLANs (VLAN IDs greater than 1005) and save configurations in the device startup configuration file. |
Interface configuration |
While in global configuration mode, enter the interface command (with a specific interface). |
Device(config-if)#
|
To exit to global configuration mode, enter exit. To return to privileged EXEC mode, press Ctrl-Z or enter end. |
Use this mode to configure parameters for the Ethernet ports. |
Line configuration |
While in global configuration mode, specify a line with the line vty or line console command. |
Device(config-line)#
|
To exit to global configuration mode, enter exit. To return to privileged EXEC mode, press Ctrl-Z or enter end. |
Use this mode to configure parameters for the terminal line. |
You need to enter only enough characters for the device to recognize the command as unique.
This example shows how to enter the show configuration privileged EXEC command in an abbreviated form:
Device# show conf
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.
This table lists some error messages that you might encounter while using the CLI to configure your device.
Error Message |
Meaning |
How to Get Help |
---|---|---|
% Ambiguous command: "show con" |
You did not enter enough characters for your device to recognize the command. |
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. |
% Incomplete command. |
You did not enter all of the keywords or values required by this command. |
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. |
% Invalid input detected at ‘^’ marker. |
You entered the command incorrectly. The caret (^) marks the point of the error. |
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 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 notification to registered applications whenever the configuration changes. You can choose to have the notifications sent to the syslog.
![]() Note | Only CLI or HTTP changes are logged. |
You can enter a question mark (?) at the system prompt to display a list of commands available for each command mode. You can also obtain a list of associated keywords and arguments for any command.
1.
help
2.
abbreviated-command-entry
?
3.
abbreviated-command-entry <Tab>
4.
?
5.
command
?
6.
command keyword ?
How to Use the CLI to Configure Features
The software provides a history or record of commands that you have entered. The command history feature is particularly useful for recalling long or complex commands or entries, including access lists. You can customize this feature to suit your needs.
By default, the device records ten command lines in its history buffer. You can alter this number for a current terminal session or for all sessions on a particular line. This procedure is optional.
1.
terminal history [size number-of-lines]
Command or Action | Purpose |
---|
To recall commands from the history buffer, perform one of the actions listed in this table. These actions are optional.
![]() Note | The arrow keys function only on ANSI-compatible terminals such as VT100s. |
1.
Ctrl-P or use the up arrow key
2.
Ctrl-N or use the down arrow key
3.
show history
The command history feature is automatically enabled. You can disable it for the current terminal session or for the command line. This procedure is optional.
1.
terminal
no history
Command or Action | Purpose |
---|
Although enhanced editing mode is automatically enabled, you can disable it and reenable it.
1.
terminal editing
2.
terminal no editing
The keystrokes help you to edit the command lines. These keystrokes are optional.
![]() Note | The arrow keys function only on ANSI-compatible terminals such as VT100s. |
Editing Commands |
Description |
||
Ctrl-B or use the left arrow key |
Moves the cursor back one character. |
||
Ctrl-F or use the right arrow key |
Moves the cursor forward one character. |
||
Ctrl-A |
Moves the cursor to the beginning of the command line. |
||
Ctrl-E |
Moves the cursor to the end of the command line. |
||
Esc B |
Moves the cursor back one word. |
||
Esc F |
Moves the cursor forward one word. |
||
Ctrl-T |
Transposes the character to the left of the cursor with the character located at the cursor. |
||
Delete or Backspace key |
Erases the character to the left of the cursor. |
||
Ctrl-D |
Deletes the character at the cursor. |
||
Ctrl-K |
Deletes all characters from the cursor to the end of the command line. |
||
Ctrl-U or Ctrl-X |
Deletes all characters from the cursor to the beginning of the command line. |
||
Ctrl-W |
Deletes the word to the left of the cursor. |
||
Esc D |
Deletes from the cursor to the end of the word. |
||
Esc C |
Capitalizes at the cursor. |
||
Esc L |
Changes the word at the cursor to lowercase. |
||
Esc U |
Capitalizes letters from the cursor to the end of the word. |
||
Ctrl-V or Esc Q |
Designates a particular keystroke as an executable command, perhaps as a shortcut. |
||
Return key |
Scrolls down a line or screen on displays that are longer than the terminal screen can display.
|
||
Space bar |
Scrolls down one screen. |
||
Ctrl-L or Ctrl-R |
Redisplays the current command line if the device suddenly sends a message to your screen. |
You can use a wraparound feature for commands that extend beyond a single line on the screen. When the cursor reaches the right margin, the command line shifts ten spaces to the left. You cannot see the first ten characters of the line, but you can scroll back and check the syntax at the beginning of the command. The keystroke actions are optional.
To scroll back to the beginning of the command entry, press Ctrl-B or the left arrow key repeatedly. You can also press Ctrl-A to immediately move to the beginning of the line.
![]() Note | The arrow keys function only on ANSI-compatible terminals such as VT100s. |
The following example shows how to wrap a command line that extends beyond a single line on the screen.
1.
access-list
2.
Ctrl-A
3.
Return key
You can search and filter the output for show and more commands. This is useful when you need to sort through large amounts of output or if you want to exclude output that you do not need to see. Using these commands is optional.
1.
{show | more} command | {begin | include | exclude}
regular-expression
You can access the CLI through a console connection, through Telnet, a SSH, or by using the browser.
You manage the switch stack and the stack member interfaces through the active switch. You cannot manage stack members on an individual switch basis. You can connect to the active switch through the console port or the Ethernet management port of one or more stack members. Be careful with using multiple CLI sessions on the active switch. Commands that you enter in one session are not displayed in the other sessions. Therefore, it is possible to lose track of the session from which you entered commands.
![]() Note | We recommend using one CLI session when managing the switch stack. |
If you want to configure a specific stack member port, you must include the stack member number in the CLI command interface notation.
To debug the standby switch, use the session standby ios privileged EXEC command from the active switch to access the IOS console of the standby switch. To debug a specific stack member, use the session switch stack-member-number privileged EXEC command from the active switch to access the diagnostic shell of the stack member. For more information about these commands, see the switch command reference.
Before you can access the CLI, you must connect a terminal or a PC to the device console or connect a PC to the Ethernet management port and then power on the device, as described in the hardware installation guide that shipped with your device.
If your device is already configured, you can access the CLI through a local console connection or through a remote Telnet session, but your device must first be configured for this type of access.
You can use one of these methods to establish a connection with the device:
Connect the device console port to a management station or dial-up modem, or connect the Ethernet management port to a PC. For information about connecting to the console or Ethernet management port, see the device hardware installation guide.
Use any Telnet TCP/IP or encrypted Secure Shell (SSH) package from a remote management station. The device must have network connectivity with the Telnet or SSH client, and the device must have an enable secret password configured.
The device supports up to 16 simultaneous Telnet sessions. Changes made by one Telnet user are reflected in all other Telnet sessions.
The device supports up to five simultaneous secure SSH sessions.
After you connect through the console port, through the Ethernet management port, through a Telnet session or through an SSH session, the user EXEC prompt appears on the management station.