Perl regex help - matching parentheses Post: 302292358

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Top Forums Shell Programming and Scripting Perl regex help - matching parentheses Post 302292358 by mneme on Friday 27th of February 2009 04:38:59 PM

02-27-2009

Registered User

The right answer here is in the perlre of modern perls:

Code:

                 The following pattern matches a parenthesized group:

                   $re = qr{
                              \(
                              (?:
                                 (?> [^()]+ )    # Non-parens without backtracking
                               |
                                 (??{ $re })     # Group with matching parens
                              )*
                              \)
                           }x;

Basically, (??{...}) embeds a regular expression (or a nested expression that chooses a regular expression) within another RE -- getting you recursive regular expressions.

If you have access to perl 5.10, you've got some other approaches available, as 5.10 has true recursive pattern matching without this kind of magic -- see here: perldelta - what is new for perl 5.10.0 - search.cpan.org

mneme

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LEARN ABOUT CENTOS

ausearch_add_regex

AUSEARCH_ADD_REGEX(3)						  Linux Audit API					     AUSEARCH_ADD_REGEX(3)

NAME

       ausearch_add_regex - use regular expression search rule

SYNOPSIS

       #include <auparse.h>

       int ausearch_add_regex(auparse_state_t *au, const char *expr);

DESCRIPTION

       ausearch_add_regex  adds  one  search condition based on a regular expression to the current audit search expression. The search conditions
       can then be used to scan logs, files, or buffers for something of interest. The regular	expression  follows  the  posix  extended  regular
       expression conventions, and is matched against the full record (without interpreting field values).

       If an existing search expression E is already defined, this function replaces it by (E && this_regexp).

RETURN VALUE

       Returns -1 if an error occurs; otherwise, 0 for success.

SEE ALSO

       ausearch_add_expression(3), ausearch_add_item(3), ausearch_clear(3), ausearch_next_event(3), regcomp(3).

AUTHOR

       Steve Grubb

Red Hat 							     Sept 2007						     AUSEARCH_ADD_REGEX(3)

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