Display Feature

When the information cannot be completely displayed on one screen, you can adopt the pause function. You have three choices, as described in Table 2-8.

Regular Expressions

A regular expression is a mode matching tool. It consists of common characters (such as letters from a to z) and special characters (called meta-characters). The regular expression is a template according to which you can search for the required string.

The regular expression consists of common characters and special characters.

• Common characters

  Common characters are used to match themselves in a string, including all upper-case and lower-case letters, digits, punctuations, and special symbols. For example, a matches the letter "a" in "abc", 10 matches the digit "10" in "10.113.25.155", and @ matches the symbol "@" in "xxx@xxx.com".

• Special characters

  Special characters are used together with common characters to match the complex or special string combination. Table 2-9 describes special characters and their syntax.

  Table 2-9 Description of special characters

  Special Characters	Function	Example
  \	Defines an escape character, which is used to mark the next character (common or special) as the common character.	\* matches "*".
  ^	Matches the starting position of the string.	^10 matches "10.10.10.1" instead of "20.10.10.1".
  $	Matches the ending position of the string.	1$ matches "10.10.10.1" instead of "10.10.10.2".
  *	Matches the preceding element zero or more times.	10* matches "1", "10", "100", "1000", and so on. (10)* matches "null", "10", "1010", "101010", and so on.
  +	Matches the preceding element one or more times.	10+ matches "10", "100", "1000", and so on. (10)+ matches "10", "1010", "101010", and so on.
  .	Matches any single character.	0.0 matches "0x0", "020", and so on. .oo. matches "book", "look", "tool", and so on.
  ()	Defines a subexpression, which can be null. Both the expression and the subexpression should be matched.	100(200)+ matches "100200", "100200200", and so on.
  x|y	Matches x or y.	100|200 matches "100" or "200". 1(2|3)4 matches "124" or "134", instead of "1234", "14", "1224", and "1334".
  [xyz]	Matches any single character in the regular expression.	[123] matches the character 2 in "255".
  [^xyz]	Matches any character that is not in the regular expression.	[^123] matches any character except for "1", "2", and "3".
  [a-z]	Matches any character within the specified range.	[0-9] matches any character ranging from 0 to 9.
  [^a-z]	Matches any character beyond the specified range.	[^0-9] matches all non-numeric characters.
  _	Matches a comma ",", left brace "{", right brace "}", left parenthesis "(", and right parenthesis ")". Matches the starting position of the input string. Matches the ending position of the input string. Matches a space.	_2008_ matches "2008", "space 2008 space", "space 2008", "2008 space", ",2008,", "{2008}", "(2008)", "{2008)", and "(2008}".

  Unless otherwise specified, all the characters in the preceding table must be printable characters.

• Degeneration of special characters

  Certain special characters, when placed at certain positions in a regular expression, degenerate to common characters.

  • The special characters following "\" match special characters themselves.

  • The special characters "*", and "+" are placed at the starting position of the regular expression. For example, +45 matches "+45" and abc(*def) matches "abc*def".

  • The special character "^" is placed at any position except for the start of the regular expression. For example, abc^ matches "abc^".

  • The special character "$" is placed at any position except for the end of the regular expression. For example, 12$2 matches "12$2".

  • A right parenthesis ")" or right bracket "]" is not paired with a corresponding left parenthesis "(" or bracket "[". For example, abc) matches "abc)" and 0-9] matches "0-9]".

  Unless otherwise specified, degeneration rules also apply when the preceding regular expressions are subexpressions within parentheses.

• Combination of common and special characters

  In actual usage, regular expressions combine multiple common and special characters to match certain strings.

Specifying a Filtering Mode in a Command

When filtering conditions are set to query output information, the first line of the command output starts with the entire regular expression but not the string to be filtered.

The system allows you to use | count to display the number of lines, | section to display the command output by section after using filtering mode, | ignore-case to match a string of case-insensitive characters, and | no-more to display filtered output information on only one screen. | count, | section, | ignore-case, and | no-more can work together with the following filtering modes.

Three filtering modes are provided for commands that support regular expressions.

• | begin regular-expression: displays all the lines beginning with the line that matches the regular expression.

  Filter the character strings to be entered until the specified case-sensitive character string is displayed. All the character strings following this specified character string are displayed on the screen.

• | exclude regular-expression: displays all the lines that do not match the regular expression.

  If the character strings to be entered do not contain the specified case-sensitive character string, they are displayed on the screen. Otherwise, they are filtered.

• | include regular-expression: displays all the lines that match the regular expression.

  If the character strings to be entered contain the specified case-sensitive character string, they are displayed on the screen. Otherwise, they are filtered.

The value of regular-expression is a string of 1 to 255 characters.

The command output can be filtered by multiple regular expressions. The regular expressions take effect in configuration sequence. A maximum of 32 regular expressions can be configured to filter the command output.

The | section parameter only applies to commands whose output information contains section information, such as the display current-configuration and display this commands.

The following examples describe how to specify a filter mode in a command.

Example 1: Run the display interface brief command to display all the lines that do not match the regular expression 10GE|40GE. 10GE|40GE matches 10GE or 40GE.

<HUAWEI> display interface brief | exclude 10GE|40GE

PHY: Physical
*down: administratively down
^down: standby
(l): loopback
(s): spoofing
(b): BFD down
(e): EFM down
(d): Dampening Suppressed
(p): port alarm down
(dl): DLDP down
InUti/OutUti: input utility rate/output utility rate
Interface                   PHY   Protocol InUti OutUti   inErrors  outErrors
Eth-Trunk2                  down  down        0%     0%          0          0
Eth-Trunk27                 up    up       0.01%  0.01%          0          0
MEth0/0/0                   up    up       0.01%  0.01%          0          0
NULL0                       up    up(s)       0%     0%          0          0
Vlanif2                     down  down        --     --          0          0
Vlanif10                    down  down        --     --          0          0
Vlanif20                    down  down        --     --          0          0
Vlanif200                   up    up          --     --          0          0

Example 2: Run the display current-configuration command to display all the lines that match the regular expression vlan.

<HUAWEI> display current-configuration | include vlan

vlan batch 2 9 to 20 77 99 200 222 4091
vlan 19
 mux-vlan
vlan 222
 aggregate-vlan
 access-vlan 1
 instance 2 vlan 2
 carrier-vlan 100
 ce-vlan 10
 port trunk allow-pass vlan 99 200
 igmp-snooping static-router-port vlan 99
 port trunk allow-pass vlan 20
 port default vlan 77
 port trunk allow-pass vlan 20

Example 3: Run the display current-configuration command to display the number of lines that match the regular expression vlan.

<HUAWEI> display current-configuration | include vlan | count
Total lines: 14.

The preceding information is used for reference only.