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User Guide for Cisco Security MARS Local Controller
78-17020-01
A P P E N D I X
B
Regular Expression Reference
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PCRE Regular Expression Details, page B-1
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Backslash, page B-2
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Circumflex and Dollar, page B-7
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Full Stop (Period, Dot), page B-8
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Matching a Single Byte, page B-8
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Square Brackets and Character Classes, page B-8
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Posix Character Classes, page B-9
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Vertical Bar, page B-10
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Internal Option Setting, page B-10
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Subpatterns, page B-11
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Named Subpatterns, page B-12
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Repetition, page B-12
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Atomic Grouping and Possessive Quantifiers, page B-14
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Back References, page B-15
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Assertions, page B-16
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Conditional Subpatterns, page B-19
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Comments, page B-20
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Recursive Patterns, page B-20
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Subpatterns as Subroutines, page B-21
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Callouts, page B-22
PCRE Regular Expression Details
The syntax and semantics of the regular expressions supported by PCRE are described below. Regular
expressions are also described in the Perl documentation and in a number of books, some of which have
copious examples. Jeffrey Friedl's "Mastering Regular Expressions", published by O'Reilly, covers
regular expressions in great detail. This description of PCRE's regular expressions is intended as
reference material.