Finding Command Options

This section provides an example of how to display syntax for a command. The syntax can consist of optional or required keywords and arguments. To display keywords and arguments for a command, enter a question mark (? ) at the configuration prompt or after entering a part of a command followed by a space.

The Cisco IOS XE software displays a list and brief description of the available keywords and arguments. For example, if you were in the global configuration mode and you want to see all the keywords or arguments for the arap command, you would type arap ? .

The <cr> symbol in the command help output stands for “carriage return.” On older keyboards, the carriage return key is the Return key. On most modern keyboards, the carriage return key is the Enter key. The <cr> symbol at the end of the command help output indicates that you have the option to press Enter to complete the command and that the arguments and keywords in the list preceding the <cr> symbol are optional. The <cr> symbol by itself indicates that no more arguments or keywords are available and that you must press Enter to complete the command.

The following examples show how you can use the question mark (? ) to assist you in entering commands.

Table 1. Finding Command Options

Command

Comment 


Router> enable
Password: <password>
Router#

Enter the enable command and password to access the privileged EXEC commands. You are in the privileged EXEC mode when the prompt changes to a “# ” from the “> ”. For example, Router> to Router# . 


Router# 
configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)#

Enter the configure terminal privileged EXEC command to enter the global configuration mode. You are in the global configuration mode when the prompt changes to Router(config)# . 


Router(config)# interface GigabitEthernet ?
  <0-6>     GigabitEthernet interface number
Router(config)# interface GigabitEthernet 1
Router(config-if)#

Enter the interface configuration mode by specifying the serial Gigabit Ethernet interface that you want to configure using the interface GigabitEthernet number global configuration command.

Enter ? to display what you must enter next on the command line.

When the system displays the <cr> symbol, you can press Enter to complete the command.

You are in the interface configuration mode when the prompt changes to Router(config-if)# .

Note 
Cisco Catalyst 8000V supports only Gigabit Ethernet interfaces.

Command

Comment

 

Router(config-if)# ?
Interface configuration commands:
  .
  .
  .
  ip                  Interface Internet Protocol config commands
  keepalive           Enable keepalive
  lan-name            LAN Name command
  llc2                LLC2 Interface Subcommands
  load-interval       Specify interval for load calculation for an
                      interface
  locaddr-priority    Assign a priority group
  logging             Configure logging for interface
  loopback            Configure internal loopback on an interface
  mac-address         Manually set interface MAC address
  mls                 mls router sub/interface commands
  mpoa                MPOA interface configuration 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
  nrzi-encoding       Enable use of NRZI encoding
  ntp                 Configure NTP
  .
  .
  .
Router(config-if)#

Enter ? to display a list of all the interface configuration commands available for the Gigabit Ethernet interface. This example shows only some of the available interface configuration commands.

Command

Comment

 

Router(config-if)# ip ?
Interface IP configuration subcommands:
  access-group          Specify access control for packets
  accounting            Enable IP accounting on this interface
  address               Set the IP address of an interface
  authentication        authentication subcommands
  bandwidth-percent     Set EIGRP bandwidth limit
  bgp                   BGP interface commands..<snipped for brevity>
  .
  .
  .
Router(config-if)# ip

Enter the command that you want to configure for the interface. This example uses the ip command.

Enter ? to display what you must enter next on the command line. This example shows only some of the available interface IP configuration commands. 


Router(config-if)# ip address ?
  A.B.C.D            IP address
  dhcp               IP Address negotiated via DHCP  pool            
   IP Address autoconfigured from a local DHCP pool
Router(config-if)# ip address

Enter the command that you want to configure for the interface. This example uses the ip address command.

Enter ? to display what you must enter next on the command line. In this example, you must enter an IP address or the negotiated keyword.

A carriage return (<cr>) is not displayed; therefore, you must enter additional keywords or arguments to complete the command.

 

Router(config-if)# ip address 172.16.0.1 ?
  A.B.C.D             IP subnet mask
Router(config-if)# ip address 172.16.0.1

Enter the keyword or the argument that you want to use. This example uses the 172.16.0.1 IP address.

Enter ? to display what you must enter next on the command line. In this example, you must enter an IP subnet mask.

A <cr> is not displayed; therefore, you must enter additional keywords or arguments to complete the command.

Command

Comment

 

Router(config-if)# ip address 172.16.0.1 255.255.255.0 ?
  secondary           Make this IP address a secondary address
  <cr>
Router(config-if)# ip address 172.16.0.1 255.255.255.0

Enter the IP subnet mask. This example uses the 255.255.255.0 IP subnet mask.

Enter ? to display what you must enter next on the command line. In this example, you can enter the secondary keyword, or you can press Enter .

A <cr> is displayed; you can press Enter to complete the command, or you can enter another keyword. 


Router(config-if)# ip address 172.16.0.1 255.255.255.0
Router(config-if)#

In this example, Enter is pressed to complete the command.

Almost every configuration command has a no form. In general, use the no form to disable a function. Use the command without the no keyword to re-enable a disabled function or to enable a function that is disabled by default. For example, IP routing is enabled by default. To disable IP routing, use the no ip routing command. To re-enable IP routing, use the ip routing command once again.

The Cisco IOS XE software command reference publications provide the complete syntax for the configuration commands and describe what the no form of a command does.

Many CLI commands also have a default form. By issuing the command default command-name, you can configure the command to its default setting. The Cisco IOS XE software command reference publications describe the function of the default form of the command when the default form performs a different function than the plain and no forms of the command.

To see what default commands are available on your system, enter default ? in the appropriate command mode.

Use the copy running-config startup-config command to save your configuration changes to the startup configuration so that the changes are not lost if the software reloads or a power outage occurs. For example: 


Router# copy running-config startup-config
Building configuration...

It might take a minute or two to save the configuration. After the configuration has been saved, the system displays the following output: 


[OK]
Router#

This task saves the configuration to NVRAM.

On the Cisco Catalyst 8000V instance, the startup configuration file is stored in the NVRAM partition. As a matter of routine maintenance on any Cisco router, users should backup the startup configuration file by copying the startup configuration file from the NVRAM to one of the router’s other file systems and in a network server. Backing up the startup configuration file provides an easy method of recovering the startup configuration file in the event the startup configuration file in the NVRAM becomes unusable for any reason.

Use the copy command to backup startup configuration files. The following examples show the startup configuration file in NVRAM being backed up:

Example 1: Copying a Startup Configuration File to Bootflash


Router# dir bootflash:
Directory of bootflash:/
   11      drwx    16384     Jan 24 2012 04:53:55 -05:00     lost+found
   12      -rw-    289243620 Jan 24 2012 04:54:55 -05:00
   308257  drwx    4096      Jan 24 2012 04:57:06 -05:00    core
   876097  drwx    4096      Jan 24 2012 04:57:07 -05:00   .prst_sync
   63277  drwx   4096     Jan 24 2012 04:57:10 -05:00 .rollback_timer   13
      -rw-       0      Jan 24 2012 04:57:19 -05:00    tracelogs.
csr1000v-adventerprisek9.2012-01-23_12.39.SSA.bin
Router# copy nvram:startup-config bootflash:
Destination filename [startup-config]? 
3517 bytes copied in 0.647 secs (5436 bytes/sec)
Directory of bootflash:/
   11      drwx    16384     Jan 24 2012 04:53:55 -05:00    lost+found
   12      -rw-    289243620 Jan 24 2012 04:54:55 -05:00
   308257  drwx    4096      Jan 24 2012 04:57:06 -05:00    core
   876097  drwx    4096      Jan 24 2012 04:57:07 -05:00   .prst_sync
   632737 drwx   4096     Jan 24 2012 04:57:10 -05:00 .rollback_timer   13
      -rw-       0      Jan 24 2012 04:57:19 -05:00    tracelogs.
csr1000v-adventerprisek9.2012-01-23_12.39.SSA.bin
   14 -rw-   7516       Jul 2 2012 15:01:39 -07:00     startup-config

Example 2: Copying a Startup Configuration File to a TFTP Server


Router# copy bootflash:startup-config tftp:
Address or name of remote host []? 172.17.16.81
Destination filename [pe24_asr-1002-confg]? /auto/tftp-users/user/startup-config
!!
3517 bytes copied in 0.122 secs (28828 bytes/sec)

For detailed information on managing configuration files, see the Managing Configuration Files section in the Configuration Fundamentals Configuration Guide.

NVRAM File Security

Cisco Catalyst 8000V allows you to encrypt some of the disk partitions internal to the VM to provide extra security around sensitive data that may be stored on the routers. For example, information in the NVRAM is encrypted so that it is not visible to administrative entities with access to the physical hard disk upon which Cisco Catalyst 8000V is stored.

You can search and filter the output of show and more commands. This functionality is useful if you need to sort through large amounts of output or if you want to exclude output that you need not see.

To use this functionality, enter a show or more command followed by the “pipe” character ( | ); one of the keywords begin , include , or exclude ; and a regular expression on which you want to search or filter (the expression is case sensitive):

show command { append | | | begin | | | exclude | | | exclude | | | include | | | redirect | | | section | | | tee } regular-expression

show command | {append | begin | exclude | include | redirect | section | tee } regular-expression

The output matches certain lines of information in the configuration file.

To power off a Cisco Catalyst 8000V instance, you must power off the VM upon which the router is installed. For information about powering off the VM, see your VM vendor documentation.