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Full Discussion: Regular expression to match multiple lines?
Top Forums Shell Programming and Scripting Regular expression to match multiple lines? Post 302884196 by LessNux on Saturday 18th of January 2014 09:24:22 AM
Old 01-18-2014
Question Regular expression to match multiple lines?
Using a regular expression, I would like multiple lines to be matched.

By default, a period (.) matches any character except newline. However, (?s) and /s modifiers are supposed to force . to accept a newline and to match any character including a newline.

However, the following two perl statements that use (?s) and /s failed to find a pattern spanning multiple lines.

Code:
perl -p -e 's/a(?s).*f/z/' srcfile > dstfile

and
Code:
perl -p -e 's/a.*f/z/s' srcfile > dstfile

where the content of srcfile is
Code:
abc
def
ghi
jkl

which can be created by

Code:
cat > srcfile << EOF
abc
def
ghi
jkl
EOF


I wanted the regular expression to match the string consisting of two lines that starts with "a" and ends with "f".

In other words, I wanted to replace
Code:
abc
def
with z.

So, I wanted dstfile to become
Code:
z
ghi
jkl

However, the above perl statements failed. The regular expressions in the above perl statements matched nothing, making dstfile identical to srcfile.

What went wrong?

What regular expression would match multiple lines?

How can a perl or bash command line find a pattern spanning multiple lines in srcfile, replace it with another, and save the modified text into dstfile?

Many thanks, in advance.
Last edited by Scott; 01-18-2014 at 10:35 AM.. Reason: More code tags
 

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LEARN ABOUT CENTOS

locale::codes::langvar

Locale::Codes::LangVar(3)				User Contributed Perl Documentation				 Locale::Codes::LangVar(3)

NAME

       Locale::Codes::LangVar - standard codes for language variation identification

SYNOPSIS

	  use Locale::Codes::LangVar;

	  $lvar = code2langvar('acm');		       # $lvar gets 'Mesopotamian Arabic'
	  $code = langvar2code('Mesopotamian Arabic'); # $code gets 'acm'

	  @codes   = all_langvar_codes();
	  @names   = all_langvar_names();

DESCRIPTION

       The "Locale::Codes::LangVar" module provides access to standard codes used for identifying language variations, such as those as defined in
       the IANA language registry.

       Most of the routines take an optional additional argument which specifies the code set to use. If not specified, the default IANA language
       registry codes will be used.

SUPPORTED CODE SETS

       There are several different code sets you can use for identifying language variations. A code set may be specified using either a name, or
       a constant that is automatically exported by this module.

       For example, the two are equivalent:

	  $lvar = code2langvar('arevela','alpha');
	  $lvar = code2langvar('arevela',LOCALE_LANGVAR_ALPHA);

       The codesets currently supported are:

       alpha
	   This is the set of alphanumeric codes from the IANA language registry, such as 'arevela' for Eastern Armenian.

	   This code set is identified with the symbol "LOCALE_LANGVAR_ALPHA".

	   This is the default code set.

ROUTINES

       code2langvar ( CODE [,CODESET] )
       langvar2code ( NAME [,CODESET] )
       langvar_code2code ( CODE ,CODESET ,CODESET2 )
       all_langvar_codes ( [CODESET] )
       all_langvar_names ( [CODESET] )
       Locale::Codes::LangVar::rename_langvar  ( CODE ,NEW_NAME [,CODESET] )
       Locale::Codes::LangVar::add_langvar  ( CODE ,NAME [,CODESET] )
       Locale::Codes::LangVar::delete_langvar  ( CODE [,CODESET] )
       Locale::Codes::LangVar::add_langvar_alias  ( NAME ,NEW_NAME )
       Locale::Codes::LangVar::delete_langvar_alias  ( NAME )
       Locale::Codes::LangVar::rename_langvar_code  ( CODE ,NEW_CODE [,CODESET] )
       Locale::Codes::LangVar::add_langvar_code_alias  ( CODE ,NEW_CODE [,CODESET] )
       Locale::Codes::LangVar::delete_langvar_code_alias  ( CODE [,CODESET] )
	   These routines are all documented in the Locale::Codes::API man page.

SEE ALSO

       Locale::Codes
	   The Locale-Codes distribution.

       Locale::Codes::API
	   The list of functions supported by this module.

       http://www.iana.org/assignments/language-subtag-registry
	   The IANA language subtag registry.

AUTHOR

       See Locale::Codes for full author history.

       Currently maintained by Sullivan Beck (sbeck@cpan.org).

COPYRIGHT

	  Copyright (c) 2011-2013 Sullivan Beck

       This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

perl v5.16.3							    2013-04-12						 Locale::Codes::LangVar(3)
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