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Full Discussion: Dangerous rm -rf command
The Lounge War Stories Dangerous rm -rf command Post 302948321 by Don Cragun on Sunday 28th of June 2015 08:58:08 PM
Old 06-28-2015
Quote:
Originally Posted by Riker1204
Code:
var="/some/place"
rm -rf "${vra}/"*

Does the rm command throw an error when ${vra} does not exist or does it simply proceed with a null byte or something followed by /* erasing everything in its path.

As a beginner in Linux / Bash everything seems to bring up a question.
This has been answered many times before. If the variable vra has not been defined, the command:
Code:
rm -rf "${vra}/"*

will invoke rm with one operand for every file in your system's root directory that does not start with a period. The rm command will then attempt to remove every file in the file hierarchies rooted in those pathnames and print a diagnostic message for every file it is unable to remove until you kill that command or wipe out your system.

UNIX and Linux system utilities are generally very happy to try to do whatever you tell them to even if you have told them to do something that could be disastrous. They don't generally try to second guess you and tell you you might be making a mistake.
 

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LEARN ABOUT CENTOS

locale::codes::langfam

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

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 v5.16.3							    2013-02-27						 Locale::Codes::LangFam(3)
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