When you first log in, the Cisco NX-OS software places you in EXEC mode. The commands available in EXEC mode include the show commands that display the device status and configuration information, the clear commands, and other commands that perform actions that you do not save in the device configuration.

Global configuration mode provides access to the broadest range of commands. The term indicates characteristics or features that affect the device as a whole. You can enter commands in global configuration mode to configure your device globally or to enter more specific configuration modes to configure specific elements such as interfaces or protocols.

One example of a specific configuration mode that you enter from global configuration mode is interface configuration mode. To configure interfaces on your device, you must specify the interface and enter interface configuration mode.

You must enable many features on a per-interface basis. Interface configuration commands modify the operation of the interfaces on the device, such as Ethernet interfaces or management interfaces (mgmt 0).

For more information about configuring interfaces, see the Cisco Nexus interfaces guide for your device.

From global configuration mode, you can access a configuration submode for configuring VLAN interfaces called subinterfaces. In subinterface configuration mode, you can configure multiple virtual interfaces on a single physical interface. Subinterfaces appear to a protocol as distinct physical interfaces.

Subinterfaces also allow multiple encapsulations for a protocol on a single interface. For example, you can configure IEEE 802.1Q encapsulation to associate a subinterface with a VLAN.

For more information about configuring subinterfaces, see the Cisco Nexus interfaces guide for your device. For details about the subinterface commands, see the command reference guide for your device.

To exit from any configuration command mode, perform one of the following tasks:

The Cisco NX-OS software supports the definition and use of variables in CLI commands.

You can refer to CLI variables in the following ways:

• Entered directly on the command line.
• Passed to a script initiated using the run-script command. The variables defined in the parent shell are available for use in the child run-script command process.

CLI variables have the following characteristics:

• Cannot have nested references through another variable
• Can persist across switch reloads or exist only for the current session

Cisco NX-OS supports one predefined variable: TIMESTAMP. This variable refers to the current time when the command executes in the format YYYY-MM-DD-HH.MM.SS.

Note	The TIMESTAMP variable name is case sensitive. All letters must be uppercase.

You can define CLI session variables to persist only for the duration of your CLI session. These variables are useful for scripts that you execute periodically. You can reference the variable by enclosing the name in parentheses and preceding it with a dollar sign ($), for example $(variable-name).

You can configure CLI variables that persist across CLI sessions and device reloads.

You can define command aliases to replace frequently used commands. The command aliases can represent all or part of the command syntax.

Command alias support has the following characteristics:

• Command aliases are global for all user sessions.

• Command aliases persist across reboots if you save them to the startup configuration.

• Command alias translation always takes precedence over any keyword in any configuration mode or submode.

• Command alias configuration takes effect for other user sessions immediately.

• The Cisco NX-OS software provides one default alias, alias, which is the equivalent to the show cli alias command that displays all user-defined aliases.

• You cannot delete or change the default command alias alias.

• You can nest aliases to a maximum depth of 1. One command alias can refer to another command alias that must refer to a valid command, not to another command alias.

• A command alias always replaces the first command keyword on the command line.

• You can define command aliases for commands in any command mode.

• If you reference a CLI variable in a command alias, the current value of the variable appears in the alias, not the variable reference.

• You can use command aliases for show command searching and filtering.

You can define command aliases for commonly used commands.

You can create a command alias for the current user session that is not available to any other user on the Cisco NX-OS device. You can also save the command alias for future use by the current user account.

You can create a list of commands in a file and execute them from the CLI. You can use CLI variables in the command script.

Note	You cannot create the script files at the CLI prompt. You can create the script file on a remote device and copy it to the bootflash:, slot0:, or volatile: directory on the Cisco NX-OS device.

You can echo information to the terminal, which is particularly useful from a command script. You can reference CLI variables and use formatting options in the echoed text.

You can delay a command action for a period of time, which is particularly useful within a command script.

You can also use other keyboard characters (such as ! or ~) as single-character patterns, but certain keyboard characters have special meanings when used in regular expressions.

To use these special characters as single-character patterns, remove the special meaning by preceding each character with a backslash (\). This example contains single-character patterns that match a dollar sign ($), an underscore (_), and a plus sign (+), respectively:

\$ \_ \+

You can also specify a pattern that contains multiple characters by joining letters, digits, or keyboard characters that do not have special meanings. For example, a4% is a multiple-character regular expression.

With multiple-character patterns, the order is important. The regular expression a4% matches the character a followed by a 4 followed by a percent sign (%). If the string does not have a4%, in that order, pattern matching fails. The multiple-character regular expression a. (the character a followed by a period) uses the special meaning of the period character to match the letter a followed by any single character. With this example, the strings ab, a!, or a2 are all valid matches for the regular expression.

You can remove the special meaning of a special character by inserting a backslash before it. For example, when the expression a\. is used in the command syntax, only the string a. will be matched.

You can match a regular expression pattern against the beginning or the end of the string by anchoring these regular expressions to a portion of the string using the special characters.

For example, the regular expression ^con matches any string that starts with con, and sole$ matches any string that ends with sole.

Note	The ^ symbol can also be used to indicate the logical function "not" when used in a bracketed range. For example, the expression [^abcd] indicates a range that matches any single letter, as long as it is not a, b, c, or d.

The Cisco NX-OS CLI provides a set of keywords that you can use with the show commands to search and filter the command output.

show version | begin Hardware

show running-config | count

show file testoutput | cut -b 1-10

show running-config | end interface

show interface brief | exclude down

show logging logfile | head lines 50

show interface brief | include up

show logging logfile | last 50

show interface brief | no-more

show version | sscp MyConnection 
show_version_output

show file testoutput | wc bytes

You can use the Global Regular Expression Print (grep) and Extended grep (egrep) command-line utilities to filter the show command output.

The grep and egrep syntax is as follows:

{grep | egrep} [count] [ignore-case] [invert-match] [line-exp] [line-number] [next lines] [prev lines] [word-exp] expression}]

You can use the less utility to display the contents of the show command output one screen at a time. You can enter less commands at the : prompt. To display all less commands you can use, enter h at the : prompt.

You can use the Stream Editor (sed) utility to filter and manipulate the show command output as follows:

sed command

The command argument contains sed utility commands.

You can control the commands that you recall from the CLI history using the Ctrl-P and Ctrl-N keystroke shortcuts. TheBy default, the Cisco NX-OS software recalls all commands from the current command mode and higher command modes. For example, if you are working in global configuration mode, the command recall keystroke shortcuts recall both EXEC mode and global configuration mode commands. Using the terminal history no-exec-in-config command, you can avoid recalling EXEC mode commands when you are in a configuration mode.

You can recall commands from the CLI history using the Ctrl-P and Ctrl-N keystroke shortcuts and edit them before reissuing them. The default edit mode is emacs. You can change the edit mode to vi.

This example shows how to define command aliases:

cli alias name ethint interface ethernet 
cli alias name shintbr show interface brief 
cli alias name shintupbr shintbr | include up | include ethernet

This example shows how to use a command alias:

switch# configure terminal
switch(config)# ethint 2/3
switch(config-if)#

This example shows how to reference a user-defined CLI session variable:

switch# show interface $(testinterface)
Ethernet2/1 is down (Administratively down)
  Hardware is 10/100/1000 Ethernet, address is 0000.0000.0000 (bia 0019.076c.4dac)
  MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA
  auto-duplex, auto-speed
  Beacon is turned off
  Auto-Negotiation is turned on
  Input flow-control is off, output flow-control is off
  Auto-mdix is turned on
  Switchport monitor is off
  Last clearing of "show interface" counters never
  5 minute input rate 0 bytes/sec, 0 packets/sec
  5 minute output rate 0 bytes/sec, 0 packets/sec
  L3 in Switched:
    ucast: 0 pkts, 0 bytes - mcast: 0 pkts, 0 bytes
  L3 out Switched:
    ucast: 0 pkts, 0 bytes - mcast: 0 pkts, 0 bytes
  Rx
    0 input packets 0 unicast packets 0 multicast packets
    0 broadcast packets 0 jumbo packets 0 storm suppression packets
    0 bytes
  Tx
    0 output packets 0 multicast packets
    0 broadcast packets 0 jumbo packets
    0 bytes
    0 input error 0 short frame 0 watchdog
    0 no buffer 0 runt 0 CRC 0 ecc
    0 overrun  0 underrun 0 ignored 0 bad etype drop
    0 bad proto drop 0 if down drop 0 input with dribble
    0 input discard
    0 output error 0 collision 0 deferred
    0 late collision 0 lost carrier 0 no carrier
    0 babble
    0 Rx pause 0 Tx pause 0 reset

This example uses $(TIMESTAMP) when redirecting show command output to a file:

switch# show running-config > rcfg.$(TIMESTAMP)
Preparing to copy....done
switch# dir
       12667     May 01 12:27:59 2008  rcfg.2008-05-01-12.27.59

Usage for bootflash://sup-local
8192 bytes used
20963328 bytes free
20971520 bytes total

This example displays the CLI commands specified in the script file:

switch# show file testfile
configure terminal
interface ethernet 2/1
no shutdown
end
show interface ethernet 2/1

This example displays the run-script command execution output:

switch# run-script testfile
`configure terminal` 
`interface ethernet 2/1` 
`no shutdown` 
`end` 
`show interface ethernet 2/1 ` 
Ethernet2/1 is down (Link not connected)
  Hardware is 10/100/1000 Ethernet, address is 0019.076c.4dac (bia 0019.076c.4dac)
  MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA
  Port mode is trunk
  auto-duplex, auto-speed
  Beacon is turned off
  Auto-Negotiation is turned on
  Input flow-control is off, output flow-control is off
  Auto-mdix is turned on
  Switchport monitor is off
  Last clearing of "show interface" counters 1d26.2uh
  5 minute input rate 0 bytes/sec, 0 packets/sec
  5 minute output rate 0 bytes/sec, 0 packets/sec
  Rx
    0 input packets 0 unicast packets 0 multicast packets
    0 broadcast packets 0 jumbo packets 0 storm suppression packets
    0 bytes
  Tx
    0 output packets 0 multicast packets
    0 broadcast packets 0 jumbo packets
    0 bytes
    0 input error 0 short frame 0 watchdog
    0 no buffer 0 runt 0 CRC 0 ecc
    0 overrun  0 underrun 0 ignored 0 bad etype drop
    0 bad proto drop 0 if down drop 0 input with dribble
    0 input discard
    0 output error 0 collision 0 deferred
    0 late collision 0 lost carrier 0 no carrier
    0 babble
    0 Rx pause 0 Tx pause 0 reset