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Full Discussion: Redirecting standard out to /dev/null goes to file "/dev/null" instead
Top Forums Shell Programming and Scripting Redirecting standard out to /dev/null goes to file "/dev/null" instead Post 302598192 by jbmorrisonjr on Monday 13th of February 2012 06:07:00 PM
Old 02-13-2012
Redirecting standard out to /dev/null goes to file "/dev/null" instead
I apologize if this question has been answered else where or is too elementary.

I ran across a KSH script (long unimportant story) that does this:

Code:
if [ blahblah ] ; then
   CAS_SRC_LOG="/var/log/cas_src.log 2>&1"
else
   CAS_SRC_LOG="/dev/null 2>&1"
fi

then does this:

Code:
    /usr/bin/echo "heartbeat: `/usr/bin/date` " >> $CAS_SRC_LOG

In other words, based on some condition, the standard output destination is set to a either a file or to null. That was the intent.

In actuality, instead of going to null, the output goes to a file /dev/"null 2>&1"


Code:
-rw-r--r--    1 root     system     76774847 Feb 13 17:07 null 2>&1

My question is, what are the substitution and command line parsing rules? Why didn't the built command line string get parsed as expected?





Thanks
John Morrison
Last edited by methyl; 06-07-2012 at 07:40 AM.. Reason: please use code tags
 

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LEARN ABOUT MOJAVE

locale::codes::langext

Locale::Codes::LangExt(3pm)				 Perl Programmers Reference Guide			       Locale::Codes::LangExt(3pm)

NAME

       Locale::Codes::LangExt - standard codes for language extension identification

SYNOPSIS

	  use Locale::Codes::LangExt;

	  $lext = code2langext('acm');		       # $lext gets 'Mesopotamian Arabic'
	  $code = langext2code('Mesopotamian Arabic'); # $code gets 'acm'

	  @codes   = all_langext_codes();
	  @names   = all_langext_names();

DESCRIPTION

       The "Locale::Codes::LangExt" module provides access to standard codes used for identifying language extensions, 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 extensions. 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:

	  $lext = code2langext('acm','alpha');
	  $lext = code2langext('acm',LOCALE_LANGEXT_ALPHA);

       The codesets currently supported are:

       alpha
	   This is the set of three-letter (lowercase) codes from the IANA language registry, such as 'acm' for Mesopotamian Arabic.

	   This is the default code set.

ROUTINES

       code2langext ( CODE [,CODESET] )
       langext2code ( NAME [,CODESET] )
       langext_code2code ( CODE ,CODESET ,CODESET2 )
       all_langext_codes ( [CODESET] )
       all_langext_names ( [CODESET] )
       Locale::Codes::LangExt::rename_langext  ( CODE ,NEW_NAME [,CODESET] )
       Locale::Codes::LangExt::add_langext  ( CODE ,NAME [,CODESET] )
       Locale::Codes::LangExt::delete_langext  ( CODE [,CODESET] )
       Locale::Codes::LangExt::add_langext_alias  ( NAME ,NEW_NAME )
       Locale::Codes::LangExt::delete_langext_alias  ( NAME )
       Locale::Codes::LangExt::rename_langext_code  ( CODE ,NEW_CODE [,CODESET] )
       Locale::Codes::LangExt::add_langext_code_alias  ( CODE ,NEW_CODE [,CODESET] )
       Locale::Codes::LangExt::delete_langext_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 v5.18.2							    2013-11-04					       Locale::Codes::LangExt(3pm)
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