|
|
The Internetwork Operating System (IOS) user interface provides access to several different command modes. Each command mode provides a group of related commands. This chapter describes how to access and list the commands available in each command mode, and explains the primary uses for each command mode.
For security purposes, the IOS provides two levels of access to commands: user and privileged. The unprivileged, user mode is called user EXEC mode. The privileged mode is called privileged EXEC mode, and requires a password. The commands available in user EXEC mode are a subset of the commands available in privileged EXEC mode.
From the privileged level, you can access global configuration mode and nine specific configuration modes: interface, subinterface, controller, map-list, map-class, line, router, ipx-router, and route-map configuration. In addition, if your router does not find a valid system image, or if its configuration file is corrupted at startup, the system might enter read-only memory (ROM) monitor mode. Entering a question mark (?) at the system prompt allows you to obtain a list of commands available for each command mode.
Almost every system configuration command also has a no form. In general, use the no form to disable a feature or function. Use the command without the keyword no to reenable a disabled feature or to enable a feature that is disabled by default. For example, IP routing is enabled by default. Specify the command no ip routing to disable IP routing and specify ip routing to reenable it. The Router Products Command Reference publication provides the complete syntax for every router configuration command and describes what the no form of a command does.
The user interface also provides context-sensitive help on command syntax. This chapter describes how to use the help system. It also describes the command editing and command history features that enable you to recall previous command entries and easily edit command entries.
For a complete description of the commands mentioned in this chapter, refer to the "User Interface Commands" chapter in the Router Products Command Reference publication.
You can perform the tasks in the following sections to become familiar with the IOS user interface:
This section describes how to access each of the IOS command modes:
Table 2-1 lists the command modes, how to access each mode, the prompt you will see while you are in that mode, the main uses for each configuration mode, and the method to exit that mode. The prompts listed assume the default router name "Router." Table 2-1 might not include all of the possible ways to access or exit each command mode.
After you log in to the router, you are automatically in user EXEC command mode. The EXEC commands available at the user level are a subset of those available at the privileged level. In general, the user EXEC commands allow you to connect to remote routers, change terminal settings on a temporary basis, perform basic tests, and list system information.
To list the user EXEC commands, complete the following task:
| Task | Command |
|---|---|
| List the user EXEC commands. | ? |
The user-level prompt consists of the router's host name followed by the angle bracket (>):
Router>
The default host name is Router unless it has been changed during initial configuration using the setup command. (Refer to the Router Products Getting Started Guide for information on the setup facility.) You can also change the router name using the hostname global configuration command described in the "System Management Commands" chapter in the Router Products Command Reference publication.
To list the commands available in user EXEC mode, enter a question mark (?) as shown in the following example:
Router> ?
Exec commands:
connect Open a terminal connection
disconnect Disconnect an existing telnet session
enable Turn on privileged commands
exit Exit from the EXEC
help Description of the interactive help system
lock Lock the terminal
login Log in as a particular user
logout Exit from the EXEC
name-connection Name an existing telnet connection
ping Send echo messages
resume Resume an active telnet connection
show Show running system information
systat Display information about terminal lines
telnet Open a telnet connection
terminal Set terminal line parameters
where List active telnet connections
Router>
The list of commands might vary slightly from this example, depending upon how your router has been configured.
Because many of the privileged commands set operating parameters, privileged access should be password-protected to prevent unauthorized use. The privileged command set includes those commands contained in user EXEC mode, as well as the configure command through which you can access the remaining command modes. Privileged EXEC mode also includes high-level testing commands, such as debug. For details on the debug command, see the Debug Command Reference publication.
To access and list the privileged EXEC commands, complete the following tasks:
| Task | Command |
|---|---|
| Step 1 Enter the privileged EXEC mode. | enable [password] |
| Step 2 List privileged EXEC commands. | ? |
If the system administrator has set a password, you are prompted to enter it before being allowed access to privileged EXEC mode. The password is not displayed on the screen and is case sensitive. The system administrator uses the enable password global configuration command to set the password that restricts access to privileged mode. This command is described in the "System Management Commands" chapter in the Router Products Command Reference publication.
The privileged-level prompt consists of the router's host name followed by the pound sign (#). (If the router was named with the hostname command, that name would appear as the prompt instead of "Router.")
Router#
The following example shows how to access privileged EXEC mode and list privileged EXEC commands:
Router> enable
Password:
Router# ?
Exec commands:
bfe For manual emergency modes setting
clear Reset functions
clock Manage the system clock
configure Enter configuration mode
connect Open a terminal connection
copy Copy a config file to or from a tftp server
debug Debugging functions
disable Turn off privileged commands
disconnect Disconnect an existing telnet session
enable Turn on privileged commands
exit Exit from the EXEC
help Description of the interactive help system
llc2 Execute llc2 tests
lock Lock the terminal
login Log in as a particular user
logout Exit from the EXEC
name-connection Name an existing telnet connection
ping Send echo messages
reload Halt and perform a cold restart
resume Resume an active telnet connection
send Send a message to other tty lines
setup Run the SETUP command facility
show Show running system information
systat Display information about terminal lines
telnet Open a telnet connection
terminal Set terminal line parameters
test Test subsystems, memory, and interfaces
trace Trace route to destination
where List active telnet connections
which-route Do route table lookup and display results
write Write running configuration to memory, network, or terminal
The list of commands might vary slightly from this example, depending upon how your router has been configured.
From the privileged level, you can access global configuration mode. For instructions, see the "Global Configuration Command Mode" section, which follows this section.
To return from privileged EXEC mode to user EXEC mode, perform the following task:
| Task | Command |
|---|---|
| Move from privileged EXEC mode to user EXEC mode. | disable |
Global configuration commands apply to features that affect the system as a whole. Use the configure privileged EXEC command to enter global configuration mode. When you enter this command, the EXEC prompts you for the source of the configuration commands:
Configuring from terminal, memory, or network [terminal]?
You can then specify either the terminal, nonvolatile memory (NVRAM), or a file stored on a network server as the source of configuration commands (see the "System Image, Microcode Image, and Configuration File Load Commands" chapter in the Router Products Command Reference publication). The default is to enter commands from the terminal console. Pressing the Return key begins this configuration method.
Commands to enable a particular routing or bridging function are also global configuration commands. For information on protocol-specific global configuration commands, see the appropriate chapter in this guide.
To access and list the global configuration commands, complete the following tasks:
| Task | Command |
|---|---|
| Step 1 At the terminal, from the privileged EXEC mode, enter global configuration mode. | configure1 <CR> |
| Step 2 List the global configuration commands. | ? |
The following example shows how to access global configuration mode and list global configuration commands:
Router# configure
Configuring from terminal, memory, or network [terminal]? <CR>
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)# ?
Configure commands:
access-list Add an access list entry
apollo Apollo global configuration commands
appletalk Appletalk global configuration commands
arp Set a static ARP entry
async-bootp Modify system bootp parameters
autonomous-system Specify local AS number to which we belong
banner Define a login banner
boot Modify system boot parameters
bridge Transparent bridging
buffers Adjust system buffer pool parameters
busy-message Display message when connection to host fails
chat-script Define a modem chat script
clns Global CLNS configuration subcommands
clock Configure time-of-day clock
decnet Global DECnet configuration subcommands
default-value Default character-bits values
dialer-list Create a dialer list entry
enable Modify enable password parameters
end Exit from configure mode
exit Exit from configure mode
frame-relay Global frame relay configuration commands
help Description of the interactive help system
hostname Set system's network name
interface Select an interface to configure
ip Global IP configuration subcommands
ipx Novell/IPX global configuration commands
line Configure a terminal line
lnm IBM Lan Manager
locaddr-priority-list Establish queueing priorities based on LU address
logging Modify message logging facilities
login-string Define a host-specific login string
mop The DEC MOP Server
netbios NETBIOS access control filtering
no Negate a command or set its defaults
ntp Configure NTP
priority-list Build a priority list
queue-list Build a custom queue list
rif Source-route RIF cache
route-map Create route-map or enter route-map command mode
router Enable a routing process
scheduler-interval Maximum interval before running lowest priority process
service Modify use of network based services
smt-queue-threshold Set the max number of unprocessed SMT frames
snmp-server Modify SNMP parameters
source-bridge Source-route bridging ring groups
stun STUN global configuration commands
tacacs-server Modify TACACS query parameters
tftp-server Provide TFTP service for netload requests
tn3270 tn3270 configuration command
username Establish User Name Authentication
vines Vines global configuration commands
x25 X.25 Level 3
xns XNS global configuration commands
The list of commands might vary slightly from this example, depending upon how your router has been configured.
To exit global configuration command mode and return to privileged EXEC mode, use one of the following commands:
| Task | Command |
|---|---|
| Exit global configuration mode. | exit end Ctrl-Z |
From global configuration mode, you can access nine configuration modes: interface, subinterface, controller, map-list, map-class, line, router, ipx-router, and route-map configuration commands. These command modes are described in the following sections.
Many features are enabled on a per-interface basis. Interface configuration commands modify the operation of an interface such as an Ethernet, FDDI, or serial port. Interface configuration commands always follow an interface global configuration command, which defines the interface type.
For details on interface configuration commands that affect general interface parameters, such as bandwidth, clock rate, and so on, see the "Configuring Interfaces" chapter. For protocol-specific commands, see the appropriate chapter in this guide.
To access and list the interface configuration commands, complete the following tasks:
| Task | Command |
|---|---|
| Step 1 From global configuration mode, enter interface configuration mode. | interface interface-type interface-number1 |
| Step 2 List the interface configuration commands. | ? |
In the following example, serial interface 0 is about to be configured. The new prompt Router(config-if)# indicates interface configuration mode. In this example, the user asks for help by requesting a list of commands.
Router(config)# interface serial 0 <CR>
Router(config-if)# ?
Interface configuration commands:
access-expression Build a bridge boolean access expression
apollo Apollo interface subcommands
appletalk Appletalk interface subcommands
arp Set arp type (arpa, probe, snap) or timeout
backup Modify dial-backup parameters
bandwidth Set bandwidth informational parameter
bridge-group Transparent bridging interface parameters
clns CLNS interface subcommands
clockrate Configure serial interface clock speed
custom-queue-list Assign a custom queue list to an interface
decnet Interface DECnet config commands
delay Specify interface throughput delay
description Interface specific description
dialer Dial-on-demand routing (DDR) commands
dialer-group Assign interface to dialer-list
down-when-looped Force looped serial interface down
encapsulation Set encapsulation type for an interface
ethernet-transit-oui Token-ring to Ethernet OUI handling
exit Exit from interface configuration mode
frame-relay Set frame relay parameters
hdh Set HDH mode
help Description of the interactive help system
hold-queue Set hold queue depth
ip Interface Internet Protocol config commands
ipx Novell interface subcommands
isis IS-IS commands
iso-igrp ISO-IGRP interface subcommands
keepalive Enable keepalive
lapb X.25 Level 2 parameters (Link Access Procedure, Balanced)
llc2 LLC2 Interface Subcommands
lnm IBM Lan Manager
locaddr-priority Assign a priority group
loopback Configure internal loopback on an interface
mac-address Manually set interface MAC address
mop DEC MOP server commands
mtu Set the interface Maximum Transmission Unit (MTU)
netbios Use a defined NETBIOS access list or enable name-caching
no Negate a command or set its defaults
ntp Configure NTP
ppp Point-to-point protocol
priority-group Assign a priority group to an interface
pulse-time Enables pulsing of DTR during resets
pup PUP interface subcommands
sdlc SDLC commands
sdllc Configure SDLC to LLC2 translation
shutdown Shutdown the selected interface
smds Modify SMDS parameters
source-bridge Configure interface for source-route bridging
stun STUN interface subcommands
transmit-interface Assign a transmit interface to a receive-only interface
transmitter-delay Set dead-time after transmitting a datagram
tunnel protocol-over-protocol tunneling
tx-queue-limit Configure card level transmit queue limit
vines Vines interface subcommands
xns XNS interface subcommands
The list of commands might vary slightly from this example, depending upon how your router has been configured.
To exit interface configuration mode and return to global configuration mode, enter the exit command. To exit configuration mode and return to privileged EXEC mode, press Ctrl-Z.
You can configure multiple virtual interfaces (called subinterfaces) on a single physical interface. This feature is supported on serial interfaces with Frame Relay encapsulation.
Subinterfaces appear to be distinct physical interfaces to the various protocols. For example, Frame Relay networks provide multiple point-to-point links called permanent virtual circuits (PVCs). PVCs can be grouped under separate subinterfaces that in turn are configured on a single physical interface. From a bridging spanning-tree viewpoint, each subinterface is a separate bridge port, and a frame arriving on one subinterface can be sent out on a another subinterface.
Subinterfaces also allow multiple encapsulations for a protocol on a single interface. For example, a router can receive an ARPA-framed IPX packet and forward the packet back out the same physical interface as a SNAP-framed IPX packet.
For detailed information on how to configure subinterfaces, see the "Configuring Interfaces" chapter, later in this publication.
To access and list the subinterface configuration commands, complete the following tasks:
| Task | Command |
|---|---|
| Step 1 From interface configuration mode, configure a virtual interface. | See the example that follows. For a list of all interface commands that allow subinterface implementation, see the "Configuring Interfaces" chapter. |
| Step 2 List the subinterface configuration commands. | ? |
In the following example, a subinterface is configured for serial line 2, which is configured for Frame Relay encapsulation. The subinterface is called 2.1 to indicate that it is subinterface 1 of serial interface 2. The new prompt Router(config-subif)# indicates subinterface configuration mode. The subinterface can be configured to support one or more Frame Relay PVCs. To list the commands available in subinterface configuration mode, enter a question mark (?).
Router(config)# interface serial 2
Router(config-if)# encapsulation frame-relay
Router(config-if)# interface serial 2.1
Router(config-subif)# ?
Interface configuration commands:
apollo Apollo interface subcommands
appletalk Appletalk interface subcommands
bandwidth Set bandwidth informational parameter
bridge-group Transparent bridging interface parameters
clns CLNS interface subcommands
decnet Interface DECnet config commands
delay Specify interface throughput delay
description Interface specific description
exit Exit from interface configuration mode
frame-relay Set frame relay parameters
ip Interface Internet Protocol config commands
ipx Novell interface subcommands
isis IS-IS commands
iso-igrp ISO-IGRP interface subcommands
no Negate a command or set its defaults
ntp Configure NTP
shutdown Shutdown the selected interface
The list of commands might vary slightly from this example depending upon how your router has been configured.
To exit subinterface configuration mode and return to global configuration mode, enter the exit command. To exit configuration mode and return to privileged EXEC mode, press Ctrl-Z.
You can configure channelized T1 interfaces in the controller configuration mode.
To access and list the controller configuration commands, complete the following tasks:
| Task | Command |
|---|---|
| Step 1 From global configuration mode, configure a channelized T1 interface. | controller t1 slot/port1 |
| Step 2 List the controller configuration commands. | ? |
In the following example, a channelized T1 interface is being configured on interface 0/0. The new prompt Router(config-controller)# indicates controller configuration mode.
Router(config)# controller t1 0/0
Router(config-controller)# ?
Controller configuration commands:
channel-group Specify the timeslots to channel-group mapping for an
interface
clocksource Specify the clock source for a DS1 link
exit Exit from controller configuration mode
framing Specify the type of Framing on a DS1 link
help Description of the interactive help system
linecode Specify the line encoding method for a DS1 link
loopback Put the entire T1 line into loopback
no Negate a command or set its defaults
shutdown Shut down a DS1 link (send Blue Alarm)
The controller configuration mode applies only to the Cisco 7000 series Multi Channel Interface Processor (MIP) that has one or two CxBus Channelized T1 (CxCT1) port adaptor modules attached.
The Asynchronous Transfer Mode (ATM) interface in the Cisco 7000 series router supports a static mapping scheme that identifies the ATM address of remote hosts or routers.
Map-list configuration commands configure a map list. They always follow a map-list global configuration command. To access and list the map list configuration commands, complete the following tasks:
| Task | Command |
|---|---|
| Step 1 From global configuration mode, use the map-list command. | map-list name1 |
| Step 2 List the map-list configuration commands. | ? |
The following example shows how to enter map-list configuration mode and list the map list configuration commands. In this example, the static map-list configuration commands are listed. The new prompt Router(config-map-list)# indicates map-list configuration mode.
Router(config)# map-list atm
Router(config-map-list)# ?
Static maps list configuration commands:
A.B.C.D Protocol specific address
aarp AppleTalk ARP
apollo Apollo Domain
appletalk AppleTalk
arp IP ARP
bridge Bridging
clns ISO CLNS
clns_es ISO CLNS End System
clns_is ISO CLNS Intermediate System
cmns ISO CMNS
compressedtcp Compressed TCP
decnet DECnet
decnet_node DECnet Node
decnet_prime_router DECnet Prime Router
decnet_router DECnet Router
exit-class Exit from static map class configuration mode
help Description of the interactive help system
ip IP
ipx Novell IPX
no Negate or set default values of a command
pad PAD links
rsrb Remote Source-Route Bridging
stun Serial Tunnel
vines Banyan VINES
xns Xerox Network Services
The list of commands might vary slightly from this example, depending upon how your router has been configured.
To exit map-list configuration mode and return to global configuration mode, enter the exit command. To exit configuraton mode an return to privileged EXEC mode, pres Ctrl-Z.
The ATM interface allows you to specify Quality of Service (QOS) parameters that control how much traffic the source router will be sending over a switched virtual circuit (SVC).
To define QOS parameters that are associated with a static map for an SVC, use the map-class global configuration command.
| Task | Command |
|---|---|
| Step 1 From global configuration mode, configure a map class. | map-class encapsulation class-name1 |
| Step 2 List the map-class configuration commands. | ? |
In the following example, the static map-class configuration commands are listed. The new prompt Router(config-map-class)# indicates map-class configuration mode.
Router(config)# map-class atm aaa
Router(config-map-class)# ?
Static maps class configuration commands:
atm Configure atm static map class
exit-class Exit from static map class configuration mode
help Description of the interactive help system
no Negate or set default values of a command
The list of commands might vary slightly from this example, depending upon how your router has been configured.
To exit map-class configuration mode and return to global configuration mode, enter the exit command. To exit configuraton mode an return to privileged EXEC mode, pres Ctrl-Z.
Line configuration commands modify the operation of a serial terminal line. Line configuration commands always follow a line command, which defines a line number. These commands are generally used to connect to remote routers, change terminal parameter settings on a line-by-line basis, and set up the auxiliary port modem configuration to support dial-on-demand routing (DDR) (see the "DDR Commands" chapter in the Router Products Command Reference publication).
To access and list the auxiliary port, console port, and virtual terminal line configuration commands, complete the following tasks:
| Task | Command |
|---|---|
| Step 1 From global configuration mode, configure an auxiliary, console, or virtual terminal line. | line {aux | con | vty} line-number [ending-line-number]1 |
| Step 2 List the line configuration commands. | ? |
The following example shows how to enter line configuration mode for virtual terminal line 3 and list the line configuration commands. The new prompt Router(config-line)# indicates line configuration mode.
Router(config)# line vty 3 <CR>
Router(config-line)# ?
Line configuration commands:
access-class Filter connections based on an IP access list
activation-character Define the activation character
autobaud Set line to autobaud
autocommand Automatically execute an EXEC command
autohangup Automatically hangup when last connection closes
autohost Automatically connect to a host
cts-required Require CTS on line
data-character-bits Size of characters being handled
databits Set number of data bits per character
disconnect-character Define the disconnect character
dispatch-character Define the dispatch character
dispatch-timeout Set the dispatch timer
editing Enable command line editing
escape-character Change the current line's escape character
exec Start an EXEC process
exec-banner Enable the display of the EXEC banner
exec-character-bits Size of characters to the command exec
exec-timeout Set the EXEC timeout
exit Exit from line configuration mode
flowcontrol Set the flow control
help Description of the interactive help system
history Enable the command history function
hold-character Define the hold character
length Set number of lines on a screen
location Enter terminal location description
lockable Allow users to lock a line
login Enable password checking
modem Configure the Modem Control Lines
monitor Copy debug output to the current terminal line
no Negate a command or set its defaults
notify Inform users of output from concurrent sessions
padding Set padding for a specified output character
parity Set terminal parity
password Set a password
private Configuration options that user can set will remain in effect
between terminal sessions
refuse-message Define a refuse banner
rotary Add line to a rotary group
rxspeed Set the receive speed
session-limit Set maximum number of sessions
session-timeout Set interval for closing connection when there is no input traffic
special-character-bits Size of the escape (and other special) characters
speed Set the transmit and receive speeds
start-character Define the start character
stop-character Define the stop character
stopbits Set async line stop bits
telnet Telnet protocol-specific configuration
telnet-transparent Send a CR as a CR followed by a NULL instead of a CR followed
by a LF
terminal-type Set the terminal type
transport Define transport protocols for line
txspeed Set the transmit speeds
vacant-message Define a vacant banner
width Set width of the display terminal
The list of commands might vary from this example, depending upon how your router has been configured.
To exit line configuration mode and return to global configuration mode, use the exit command. To exit configuration mode and return to privileged EXEC mode, press Ctrl-Z.
Router configuration commands configure a routing protocol and always follow a router command. To access and list the router configuration commands, complete the following tasks:
| Task | Command |
|---|---|
| Step 1 From global configuration mode, enter router configuration mode. | router [keyword]1 See the list in the example for keywords. |
| Step 2 List the router configuration commands. | ? |
To list the available router configuration keywords, enter the router command followed by a space and a question mark (?) at the global configuration prompt:
Router(config)# router ?
bgp Border Gateway Protocol (BGP)
egp Exterior Gateway Protocol (EGP)
igrp Interior Gateway Routing Protocol (IGRP)
isis ISO IS-IS
iso-igrp IGRP for OSI networks
ospf Open Shortest Path First (OSPF)
rip Routing Information Protocol (RIP)
static Static CLNS Routing
In the following example, the router is configured to support the Routing Information Protocol (RIP). The new prompt is Router(config-router)#.
Router(config)# router rip
Router(config-router)# ?
router configuration commands:
default-information Control distribution of default information
default-metric Set metric of redistributed routes
distance Define an administrative distance
distribute-list Filter networks in routing updates
exit Exit from routing protocol configuration mode
help Description of the interactive help system
neighbor Specify a neighbor router
network Enable routing on an IP network
no Negate or set default values of a command
offset-list Add or subtract offset from IGRP, RIP, or HELLO metrics
passive-interface Suppress routing updates on an interface
redistribute Redistribute information from another routing protocol
timers Adjust routing timers
The list of commands might vary slightly from this example, depending upon how your router has been configured.
To exit router configuration mode and return to global configuration mode, enter the exit command. To exit configuration mode and return to privileged EXEC mode, press Ctrl-Z.
Internet Packet Exchange (IPX) is a Novell network-layer protocol. To access and list the IPX routing configuration commands, complete the following tasks:
| Task | Command |
|---|---|
| Step 1 From global configuration mode, enter IPX-router configuration mode. | ipx router [keyword]1 See the Novell IPX chapter for keywords. |
| Step 2 List the IPX-router configuration commands. | ? |
In the following example, IPX RIP routing is configured. The new prompt is Router(config-ipx-router)#.
Router(config)# ipx router rip<CR>
Router(config-ipx-router)# ?
Novell router configuration commands:
distribute-list Filter networks in routing updates
exit Exit from IPX routing protocol configuration mode
help Description of the interactive help system
network Enable routing on an IPX network
no Negate or set default values of a command
redistribute Enable routing protocol redistribution
To exit IPX-router configuration mode and return to global configuration mode, enter the exit command. To exit configuration mode and return to privileged EXEC mode, press Ctrl-Z.
Use the route-map configuration mode to configure routing table and source and destination information. To access and list the route-map configuration commands, complete the following tasks:
| Task | Command |
|---|---|
| Step 1 From global configuration mode, enter route-map configuration mode. | route-map [route map tag]1 |
| Step 2 List the route-map configuration commands. | ? |
In the following example, a route map named arizona1 is configured. The new prompt is Router(config-route-map)#. Enter a question mark (?) to list route-map configuration commands.
Router(config)# route-map arizona1 <CR>
Router(config-route-map)# ?
Route Map configuration commands:
exit Exit from route-map configuration mode
help Description of the interactive help system
match Match values from routing table
no Negate or set default values of a command
set Set values in destination routing protocol
To exit route-map configuration mode and return to global configuration mode, enter the exit command. To exit configuration mode and return to privileged EXEC mode, press Ctrl-Z.
If your router does not find a valid system image, or if its configuration file is corrupted at startup, the system might enter read-only memory (ROM) monitor mode. From ROM monitor mode, you can boot the router or perform diagnostic tests.
From the Cisco 2000, Cisco 3000, and Cisco 4000, you can also enter ROM monitor mode by entering the reload EXEC command and then pressing the Break key during the first 60 seconds of startup. To save changes to the configuration file, use the write memory command before issuing the reload command.
To access and list the ROM monitor configuration commands, complete the following tasks:
| Task | Command |
|---|---|
| Enter ROM monitor mode from privileged EXEC mode. | reload1 Press Break during the first 60 seconds while the system is booting. |
| List the ROM monitor commands. | ? |
The ROM monitor prompt is the angle bracket (>):
> ?
$ state Toggle cache state (? for help)
B [filename] [TFTP Server IP address | TFTP Server Name]
Load and execute system image from ROM or from TFTP server
C [address] Continue execution [optional address]
D /S M L V Deposit value V of size S into location L with modifier M
E /S M L Examine location L with size S with modifier M
G [address] Begin execution
H Help for commands
I Initialize
K Stack trace
L [filename] [TFTP Server IP address | TFTP Server Name]
Load system image from ROM or from TFTP server, but do not
begin execution
O Show configuration register option settings
P Set the break point
S Single step next instruction
T function Test device (? for help)
Deposit and Examine sizes may be B (byte), L (long) or S (short).
Modifiers may be R (register) or S (byte swap).
Register names are: D0-D7, A0-A6, SS, US, SR, and PC
To return to user EXEC mode, enter c to continue. To boot the system image file, use the b command (described in the "System Image, Microcode Image, and Configuration File Load Commands" chapter in the Router Products Command Reference publication). For details on other ROM monitor mode commands, refer to the appropriate hardware installation guide.
The previous sections described the first level of help available with the user interface. Entering a question mark (?) at the system prompt displays a list of commands available for each command mode. You can also get a list of any command's associated keywords and arguments with the context-sensitive help feature.
To get help specific to a command mode, a command, a keyword, or arguments, perform one of the following tasks:
| Task | Command |
|---|---|
| Obtain a brief description of the help system in any command mode. | help |
| Obtain help for the full set of user-level commands. | full-help |
| Obtain help for the full set of user-level commands in user EXEC command mode. | terminal full-help1 |
| Obtain a list of commands that begin with a particular character string. | abbreviated-command-entry? |
| Complete a partial command name. | abbreviated-command-entry<Tab> |
| List all commands available for a particular command mode. | ? |
| List a command's associated keywords. | command ? |
| List a keyword's associated arguments. | command keyword ? |
When using context-sensitive help, the space (or lack of a space) before the question mark (?) is significant. To obtain a list of commands that begin with a particular character sequence, type in those characters followed immediately by the question mark (?). Do not include a space. This form of help is called word help, because it completes a word for you.
To list keywords or arguments, enter a questio mark (?) in place of a keyword or argument. Include a space before the ?. 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 already have entered.
You can abbreviate commands and keywords to the number of characters that allow a unique abbreviation. For example, you can abbreviate the show command to sh.
Enter the help command (which is available in any command mode) for a brief description of the help system:
Router# help
Help may be requested at any point in a command by entering
a question mark '?'. If nothing matches, the help list will
be empty and you must back up until entering a '?' shows the
available options.
Two styles of help are provided:
1. Full help is available when you are ready to enter a
command argument (e.g. 'show ?') and describes each possible
argument.
2. Partial help is provided when an abbreviated argument is entered
and you want to know what arguments match the input
(e.g. 'show pr?'.)
As described in the help command output, you can enter a partial command name and a question mark (?) to obtain a list of commands beginning with a particular character set. See "Complete a Partial Command Name" later in this chapter for more detail.
The following example illustrates how the context-sensitive help feature enables you to create an access list from configuration mode. First enter the letters co at the system prompt followed by a question mark (?). Do not leave a space between the last letter and the question mark (?). The system provides the commands that begin with co.
Router# co?
configure connect copy
Enter the configure command followed by a space and a question mark (?) to list the command's keywords and a brief explanation:
Router# configure ?
memory Configure from NV memory
network Configure from a TFTP network host
terminal Configure from the terminal
<cr>
Enter the terminal keyword to enter configuration mode from the terminal:
Router# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)#
Enter the access-list command followed by a space and a question mark (?) to list the command's keywords:
Router(config)# access-list ?
<1-99> IP standard access list
<100-199> IP extended access list
<1000-1099> IPX SAP access list
<1100-1199> Extended 48-bit MAC address access list
<200-299> Protocol type-code access list
<300-399> DECnet access list
<400-499> XNS standard access list
<500-599> XNS extended access list
<600-699> Appletalk access list
<700-799> 48-bit MAC address access list
<800-899> IPX standard access list
<900-999> IPX extended access list
Enter the access list number 99 and then enter another question mark (?) to see the arguments that apply to the keyword and brief explanations:
Router(config)# access-list 99 ?
deny Specify packets to reject
permit Specify packets to forward
Enter the deny argument followed by a question mark (?) to list additional options:
Router(config)# access-list 99 deny ?
A.B.C.D Address to match
Enter the IP address followed by a question mark (?) to list additional options:
Router(config)# access-list 99 deny 131.108.134.0 ?
A.B.C.D Mask of bits to ignore
<cr>
The <cr> symbol appears in the list, indicating that one of your options is to press Return to execute the command. The other option is to add a wildcard mask. Enter the wildcard mask followed by a question mark (?) to list further options.
Router(config)# access-list 99 deny 131.108.134.0 0.0.0.255 ?
<cr>
Router(config)# access-list 99 deny 131.108.134.0 0.0.0.255
The <cr> symbol by itself indicates there are no more keywords or arguments. Press Return to execute the command. The system adds an entry to access list 99 that denies access to all hosts on subnet 131.108.134.0.
The user interface provides syntax checking in the form of an error location indicator (^). The ^ symbol appears at the point in the command string where you have entered an incorrect command, keyword, or argument. The error location indicator and interactive help system allow you to easily find and correct syntax errors.
In the following example, suppose you want to set the router clock. First, use context-sensitive help to check the syntax for setting the clock.
Router# clock ?
set Set the time and date
Router# clock
The help output shows that the set keyword is required. Next, check the syntax for entering the time:
Router# clock set ?
hh:mm:ss Current time
Router# clock set
Enter the current time:
Router# clock set 13:32:00
% Incomplete command.
The system indicates that you need to provide additional arguments to complete the command. Press Ctrl-P (see the next section, "Use the Command History Features") to automatically repeat the previous command entry. Then add a space and question mark (?) to reveal the additional arguments:
Router# clock set 13:32:00 ?
<1-31> Day of the month
January Month of the year
February
March
April
May
June
July
August
September
October
November
December
Now you can complete the command entry:
Router# clock set 13:32:00 23 February 93
^
% Invalid input detected at '^' marker.
The caret symbol (^) and help response indicate an error at 93. To list the correct syntax, enter the command up to the point where the error occurred and then enter a question mark (?):
Router# clock set 13:32:00 23 February ?
<1993-2035> Year
Router# clock set 13:32:00 23 February
Enter the year using the correct syntax and press Return to execute the command.
Router# clock set 13:32:00 23 February 1993
With the current software release, the user interface provides a history or record of commands you have entered. This feature is particularly useful for recalling long or complex commands or entries, including access lists. With the command history feature, you can complete the tasks in the following sections:
By default, the system records ten command lines in its history buffer. To set the number of command lines the system will record during the current terminal session, complete the following task in EXEC mode:
| Task | Command |
|---|---|
| Enable the command history feature for the current terminal session. | terminal history [size number-of-lines]1 |
The terminal history no size command resets to default.
To configure the number of command lines the system will record, complete the following task in line configuration mode:
| Task | Command |
|---|---|
| Enable the command history feature. | history [size number-of-lines]1 |
To recall commands from the history buffer, perform one of the following tasks:
| Task | Key Sequence/Command |
|---|---|
| Recall commands in the history buffer, beginning with the most recent command. Repeat the key sequence to recall successively older commands. | Press Ctrl-P or the up arrow key.1 |
| Return to more recent commands in the history buffer after recalling commands with Ctrl-P or the up arrow key. Repeat the key sequence to recall successively more recent commands. | Press Ctrl-N or the down arrow key.1 |
| While in EXEC mode, list the commands you have just entered. | show history |
The command history feature is automatically enabled. To disable it during the current terminal session, complete the following task in EXEC mode:
| Task | Command |
|---|---|
| Disable the command history feature for the current session. | terminal no history1 |
To configure a specific line so that the command history feature is disabled, complete the following task in line configuration mode:
| Task | Command |
|---|---|
| Configure the line so that the command history feature is disabled. | no history |
The current software release includes an enhanced editing mode that provides a set of editing key functions similar to those of the Emacs editor.
You can enter commands in uppercase, lowercase, or a mix of both. Only passwords are casesensitive. You can abbreviate commands and keywords to the number of characters that allow a unique abbreviation. For example, you can abbreviate the show command to sh. After entering the command line at the system prompt, press the Return key to execute the command.
The following subsections are included in this section:
Although enhanced editing mode is automatically enabled with the current software release, you can disable it and revert to the editing mode of previous software releases. See the section "Disable Enhanced Editing Mode" later in this chapter.
To reenable the enhanced editing mode for the current terminal session, complete the following task in EXEC mode:
| Task | Command |
|---|---|
| Enable the enhanced editing features for the current terminal session. | terminal editing1 |
To reconfigure a specific line to have enhanced editing mode, complete the following task in line configuration mode:
| Task | Command |
|---|---|
| Enable the enhanced editing features. | editing |
Perform the following tasks to move the cursor around on the command line for corrections or changes:
| Task | Keystrokes |
| Move the cursor back one character. | Press Ctrl-B or press the left arrow key.1 |
| Move the cursor forward one character. | Press Ctrl-F or press the right arrow key.1 |
| Move the cursor to the beginning of the command line. | Press Ctrl-A. |
| Move the cursor to the end of the command line. | Press Ctrl-E. |
| Move the cursor back one word. | Press Esc-B. |
| Move the cursor forward one word. | Press Esc-F. |
If you cannot remember a complete command name, you can use the Tab key to allow the system to complete a partial entry. To do so, perform the following task:
| Task | Keystrokes |
|---|---|
| Recall a complete command name. | Enter the first few letters and press the Tab key. |
If your keyboard does not have a Tab key, press Ctrl-I instead.
In the following example, when you enter the letters conf and press the Tab key, the system provides the complete command:
Router# conf<Tab>
Router# configure
If you enter a set of characters that could indicate more than one command, the system beeps to indicate an error. Enter a question mark (?) to obtain a list of commands that begin with that set of characters. Do not leave a space between the last letter and the question mark (?).
For example, there are three commands in privileged mode that start with co. To see what they are, type co? at the privileged EXEC prompt:
Router# co?
configure connect copy
Router# co
The system provides a buffer that contains the last ten items you deleted. You can recall these items and paste them in the command line by performing the following task:
| Task | Keystrokes |
|---|---|
| Step 1 Recall the most recent entry in the buffer. | Press Ctrl-Y. |
| Step 2 Recall the next buffer entry. | Press Esc-Y. |
The buffer contains only the last ten items you have deleted or cut. If you press Esc-Y more than ten times, you will cycle back to the first buffer entry.
The new editing command set provides 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. To scroll back, perform the following task:
| Task | Keystrokes |
|---|---|
| Return to the beginning of a command line to verify that you have entered a lengthy command correctly. | Press Ctrl-B or the left arrow key repeatedly until you scroll back to the beginning of the command entry, or press Ctrl-A to return directly to the beginning of the line.1 |
In the following example, the access-list command entry extends beyond one line. When the cursor first reaches the end of the line, the line is shifted ten spaces to the left and redisplayed. The dollar sign ($) indicates that the line has been scrolled to the left. Each time the cursor reaches the end of the line, the line is again shifted ten spaces to the left.
Router(config)# access-list 101 permit tcp 131.108.2.5 255.255.255.0 131.108.1
Router(config)# $ 101 permit tcp 131.108.2.5 255.255.255.0 131.108.1.20 255.25
Router(config)# $t tcp 131.108.2.5 255.255.255.0 131.108.1.20 255.255.255.0 eq
Router(config)# $108.2.5 255.255.255.0 131.108.1.20 255.255.255.0 eq 45
When you have completed the entry, press Ctrl-A to check the complete syntax before pressing the Return key to execute the command. The dollar sign ($) appears at the end of the line to indicate that the line has been scrolled to the right:
Router(config)# access-list 101 permit tcp 131.108.2.5 255.255.255.0 131.108.1$
The router assumes you have a terminal screen that is 80 columns wide. If you have a width other than that, use the terminal width command to tell the router the correct width of your terminal.
Use line wrapping in conjunction with the command history feature to recall and modify previous complex command entries. See the section "Recall Commands" earlier in this chapter for information about recalling previous command entries.
Perform any of the following tasks to delete command entries if you make a mistake or change your mind:
| Task | Keystrokes |
|---|---|
| Erase the character to the left of the cursor. | Press the Delete or Backspace key. |
| Delete the character at the cursor. | Press Ctrl-D. |
| Delete all characters from the cursor to the end of the command line. | Press Ctrl-K. |
| Delete all characters from the cursor to the beginning of the command line. | Press Ctrl-U or Ctrl-X. |
| Delete the word to the left of the cursor. | Press Ctrl-W. |
| Delete from the cursor to the end of the word. | Press Esc-D. |
When you use the help facility to list the commands available in a particular mode, the list is often longer than the terminal screen can display. In such cases, a ---More--- prompt is displayed at the bottom of the screen. To view the next line or screen, complete the following tasks:
| Task | Keystrokes |
|---|---|
| Scroll down one line. | Press the Return key. |
| Scroll down one screen. | Press the Space bar. |
---More--- prompt is used for any output that has more lines than can be displayed on the terminal screen, including show command output. You can use the keystrokes listed above whenever you see the ---More--- prompt.
If you are entering a command and the system suddenly sends a message to your screen, you can easily recall your current command line entry. To do so, perform the following task:
| Task | Keystrokes |
|---|---|
| Redisplay the current command line. | Press Ctrl-L or Ctrl-R. |
If you have mistyped a command entry, you can transpose the mistyped characters by performing the following task:
| Task | Keystrokes |
|---|---|
| Transpose the character to the left of the cursor with the character located at the cursor. | Press Ctrl-T. |
You can capitalize or lowercase words or capitalize a set of letters with simple keystroke sequences. To do so, perform the following task:
| Task | Keystrokes |
|---|---|
| Capitalize the word at the cursor. | Press Esc-C. |
| Change the word at the cursor to lowercase. | Press Esc-L. |
| Capitalize letters from the cursor to the end of the word. | Press Esc-U. |
Sometimes you might want to use a particular keystroke as an executable command, perhaps as a shortcut. Complete the following task to insert a system code for this purpose:
| Task | Keystrokes |
|---|---|
| Insert a code to indicate to the system that the keystroke immediately following should be treated as a command entry, not an editing key. | Press Ctrl-V or Esc-Q. |
To disable enhanced editing mode and revert to the editing mode of software releases before 9.21, perform the following task in EXEC mode:
| Task | Command |
|---|---|
| Disable the enhanced editing features for the local line. | terminal no editing1 |
You might want to disable enhanced editing if you have prebuilt scripts; for example, scripts that do not interact well when enhanced editing is enabled. You can reenable enhanced editing mode with the terminal editing command.
The editing keys and functions of software releases before 9.21 are listed in Table 2-2.
| Key | Function |
|---|---|
| Delete or Backspace | Erases the character to the left of the cursor. |
| Ctrl-W | Erases a word. |
| Ctrl-U | Erases a line. |
| Ctrl-R | Redisplays a line. |
| Ctrl-Z | Ends configuration mode and returns to the EXEC prompt. |
| Return | Executes single-line commands. |
|
|