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Full Discussion: Understanding sed
Top Forums Shell Programming and Scripting Understanding sed Post 302774419 by gary_w on Friday 1st of March 2013 10:20:39 PM
Old 03-01-2013
An attempt to further explain the regular expression, with an ulterior motive of setting up for a question.

Given:
Code:
sed 's/^\([^:]*\):[^:]:/\1::/'

search for a pattern in the string matching:
Code:
^    = start of the line
\(   = Start of first remembered pattern
[^:] = followed by any character that is not a :
*    = followed by any number of the previous character class
       (characters that are not colons)
\)   = end of first remembered pattern
:    = followed by a colon
[^:] = followed by any character that is not a colon
:    = followed by a colon

<describes the first 2 fields, along with their seperators>

Replace with:
Code:
\1   = the first remembered pattern (the first field)
::   = followed by 2 literal colons

In other words, replace the first 2 colon separated fields
with the first field and 2 colons (deletes the 2nd field).

Question: if this sed command was in a script, could it be commented like I did above in the code? Can a sed regex be multi-line with comments?

One could also do:
Code:
s/:[^:]*:/::/

 

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LEARN ABOUT DEBIAN

locale::script

Locale::Script(3perl)					 Perl Programmers Reference Guide				     Locale::Script(3perl)

NAME

       Locale::Script - standard codes for script identification

SYNOPSIS

	  use Locale::Script;

	  $script  = code2script('phnx');		      # 'Phoenician'
	  $code    = script2code('Phoenician'); 	      # 'Phnx'
	  $code    = script2code('Phoenician',
				 LOCALE_CODE_NUMERIC);	      # 115

	  @codes   = all_script_codes();
	  @scripts = all_script_names();

DESCRIPTION

       The "Locale::Script" module provides access to standards codes used for identifying scripts, such as those defined in ISO 15924.

       Most of the routines take an optional additional argument which specifies the code set to use. If not specified, the default ISO 15924
       four-letter codes will be used.

SUPPORTED CODE SETS

       There are several different code sets you can use for identifying scripts. The ones currently supported are:

       alpha
	   This is a set of four-letter (capitalized) codes from ISO 15924 such as 'Phnx' for Phoenician.

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

	   The Zxxx, Zyyy, and Zzzz codes are not used.

	   This is the default code set.

       numeric
	   This is a set of three-digit numeric codes from ISO 15924 such as 115 for Phoenician.

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

ROUTINES

       code2script ( CODE [,CODESET] )
       script2code ( NAME [,CODESET] )
       script_code2code ( CODE ,CODESET ,CODESET2 )
       all_script_codes ( [CODESET] )
       all_script_names ( [CODESET] )
       Locale::Script::rename_script  ( CODE ,NEW_NAME [,CODESET] )
       Locale::Script::add_script  ( CODE ,NAME [,CODESET] )
       Locale::Script::delete_script  ( CODE [,CODESET] )
       Locale::Script::add_script_alias  ( NAME ,NEW_NAME )
       Locale::Script::delete_script_alias  ( NAME )
       Locale::Script::rename_script_code  ( CODE ,NEW_CODE [,CODESET] )
       Locale::Script::add_script_code_alias  ( CODE ,NEW_CODE [,CODESET] )
       Locale::Script::delete_script_code_alias  ( CODE [,CODESET] )
	   These routines are all documented in the Locale::Codes man page.

SEE ALSO

       Locale::Codes
       Locale::Constants
       http://www.unicode.org/iso15924/
	   Home page for ISO 15924.

AUTHOR

       See Locale::Codes for full author history.

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

COPYRIGHT

	  Copyright (c) 1997-2001 Canon Research Centre Europe (CRE).
	  Copyright (c) 2001-2010 Neil Bowers
	  Copyright (c) 2010-2011 Sullivan Beck

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

perl v5.14.2							    2011-09-26						     Locale::Script(3perl)
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