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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::langfam5.18

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

NAME

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

SYNOPSIS

	  use Locale::Codes::LangFam;

	  $lext = code2langfam('apa');		       # $lext gets 'Apache languages'
	  $code = langfam2code('Apache languages');    # $code gets 'apa'

	  @codes   = all_langfam_codes();
	  @names   = all_langfam_names();

DESCRIPTION

       The "Locale::Codes::LangFam" module provides access to standard codes used for identifying language families, such as those as defined in
       ISO 639-5.

       Most of the routines take an optional additional argument which specifies the code set to use. If not specified, the default ISO 639-5
       language family codes will be used.

SUPPORTED CODE SETS

       There are several different code sets you can use for identifying language families. 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 = code2langfam('apa','alpha');
	  $lext = code2langfam('apa',LOCALE_LANGFAM_ALPHA);

       The codesets currently supported are:

       alpha
	   This is the set of three-letter (lowercase) codes from ISO 639-5 such as 'apa' for Apache languages.

	   This is the default code set.

ROUTINES

       code2langfam ( CODE [,CODESET] )
       langfam2code ( NAME [,CODESET] )
       langfam_code2code ( CODE ,CODESET ,CODESET2 )
       all_langfam_codes ( [CODESET] )
       all_langfam_names ( [CODESET] )
       Locale::Codes::LangFam::rename_langfam  ( CODE ,NEW_NAME [,CODESET] )
       Locale::Codes::LangFam::add_langfam  ( CODE ,NAME [,CODESET] )
       Locale::Codes::LangFam::delete_langfam  ( CODE [,CODESET] )
       Locale::Codes::LangFam::add_langfam_alias  ( NAME ,NEW_NAME )
       Locale::Codes::LangFam::delete_langfam_alias  ( NAME )
       Locale::Codes::LangFam::rename_langfam_code  ( CODE ,NEW_CODE [,CODESET] )
       Locale::Codes::LangFam::add_langfam_code_alias  ( CODE ,NEW_CODE [,CODESET] )
       Locale::Codes::LangFam::delete_langfam_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.loc.gov/standards/iso639-5/id.php
	   ISO 639-5 .

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::LangFam(3pm)
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