Cisco ASR 9000 User Manual (English)

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A-156

Cisco ASR 9000 Series Aggregation Services Router Getting Started Guide

OL-28417-02

Chapter Understanding Regular Expressions, Special Characters, and Patterns

Pattern Alternation

The order for matches using multipliers (*, +, and ?) is to put the longest construct first. Nested

constructs are matched from outside to inside. Concatenated constructs are matched beginning at the left

side of the construct. Thus, the regular expression matches A9b3, but not 9Ab3 because the letters are

specified before the numbers.

Pattern Alternation

Alternation can be used to specify alternative patterns to match against a string. Separate the alternative

patterns with a vertical bar (

|). Only one of the alternatives can match the string. For example, the regular

expression codex

|telebit matches the string codex or the string telebit, but not both codex and telebit.

Anchor Characters

Anchoring can be used to match a regular expression pattern against the beginning or end of the string.

Table 39 shows that regular expressions can be anchored 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.

In addition to indicating the beginning of a string, the ^ can 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 the letters a, b, c, and d.

Underscore Wildcard

Use the underscore to match the beginning of a string (^), the end of a string ($), space ( ), braces ({}),

comma (,), and underscore (_). With the underscore character, you can specify that a pattern exists

anywhere in the input string. For example, _1300_ matches any string that has 1300 somewhere in the

string and is preceded by or followed by a space, brace, comma, or underscore. Although _1300_

matches the regular expression {1300_, it does not match the regular expressions 21300 and 13000.

The underscore can replace long regular expression lists. For example, instead of specifying

^1300$ {1300, ,1300, {1300}, simply specify _1300_.

Ta b l e 39 Special Characters Used for Anchoring

Character Description

^ Matches the beginning of the string.

$ Matches the end of the string.

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Cisco ASR 9000 Specifications

General

Operating System	Cisco IOS XR
Management	CLI, SNMP, NETCONF, RESTCONF
Type	Edge Router
Interface Support	10G, 40G, 100G, 400G
Power Supply	AC and DC options available
Routing Protocol	BGP, IS-IS, OSPF, EIGRP
Storage	SSD
Operating Temperature	0 to 40°C (32 to 104°F)
Humidity	5 to 95% (noncondensing)
Redundancy	Yes (Power, Fabric, Route Processor)
MTBF	Varies by model (typically > 200, 000 hours)