Special Characters

Appendix A Understanding Regular Expressions, Special Characters, and Patterns

Special Characters

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Certain keyboard characters have special meaning when used in regular expressions. Table A-1lists the keyboard characters that have special meaning.

Table A-1	Characters with Special Meaning

Character		Special Meaning

.		Matches any single character, including white space.

*		Matches 0 or more sequences of the pattern.

+		Matches 1 or more sequences of the pattern.

?		Matches 0 or 1 occurrences of the pattern.

^		Matches the beginning of the string.

$		Matches the end of the string.

_ (underscore)		Matches a comma (,), left brace ({), right brace (}), left parenthesis ( ( ), right
		parenthesis ( ) ), the beginning of the string, the end of the string, or a space.

To use these special characters as single-character patterns, remove the special meaning by preceding each character with a backslash (\). In the following examples, single-character patterns matching a dollar sign, an underscore, and a plus sign, respectively, are shown.

\$ \_ \+

Character Pattern Ranges

A range of single-character patterns can be used to match command output. To specify a range of single-character patterns, enclose the single-character patterns in square brackets ([ ]). Only one of these characters must exist in the string for pattern-matching to succeed. For example, [aeiou] matches any one of the five vowels of the lowercase alphabet, while [abcdABCD] matches any one of the first four letters of the lowercase or uppercase alphabet.

Simplify a range of characters by entering only the endpoints of the range separated by a dash (–), as in the following example:

[a–dA–D]

To add a dash as a single-character pattern in the search range, include another dash and precede it with a backslash:

[a–dA–D\–]

A bracket (]) can also be included as a single-character pattern in the range:

[a–dA–D\–\]]

Invert the matching of the range by including a caret (^) at the start of the range. The following example matches any letter except the ones listed:

[^a–dqsv]

The following example matches anything except a right square bracket (]) or the letter d:

[^\]d]

Cisco ASR 9000 Series Aggregation Services Router Getting Started Guide

	A-2	OL-17502-01

A9KMOD80TR, A9K24X10GETR, ASR 9000 specifications

Cisco Systems has long been a leader in networking technology, providing cutting-edge solutions for service providers and enterprise organizations alike. Among their standout products is the Cisco ASR 9000 Series Aggregation Services Routers, notably the A9K24X10GETR and the A9KMOD80TR models. These routers are engineered to deliver unmatched performance, scalability, and versatility for networks that require high bandwidth and low latency.

The Cisco ASR 9000 Series is built for the needs of today's complex service provider and enterprise networks. A significant feature of the A9K24X10GETR is its 24-port 10-Gigabit Ethernet module. This functionality allows for high-density connectivity, making it ideal for aggregating numerous connections to different parts of a network while maintaining optimal performance. Whether used for Internet service providers delivering high-speed connectivity or for enterprises looking to connect multiple branches, the A9K24X10GETR provides robust and reliable data transmission.

Further enhancing the capabilities of the ASR 9000 is the A9KMOD80TR module, which supports an extensive range of services. This module is designed to run a variety of technologies, including Layer 2 and Layer 3 services, MPLS (Multiprotocol Label Switching), and IPv6. Its ability to integrate seamlessly into existing infrastructures while providing the advanced features customers demand makes it an invaluable asset for network engineering teams.

Another cutting-edge technology present in the ASR 9000 Series is its support for eBGP (External Border Gateway Protocol), which plays a critical role in managing traffic across multiple networks. The routers are equipped with advanced telemetry features, empowering operators with real-time insights into network performance and health. Additionally, they come with integrated security features that protect against DDoS threats and other vulnerabilities.

In summary, Cisco's ASR 9000 Series, particularly the A9K24X10GETR and A9KMOD80TR, combines high-density connections, extensive service support, and advanced security and telemetry capabilities. These routers are perfect for demanding environments where reliable performance and adaptability are crucial. With their focus on innovation and performance, Cisco continues to shape the future of networking technology.

Cisco Systems ASR 9000 Special Characters, Character Pattern Ranges, Character Special Meaning

Models: A9KMOD80TR A9K24X10GETR ASR 9000

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