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Full Discussion: Help to write bash script code
Top Forums Shell Programming and Scripting Help to write bash script code Post 302527947 by tukuyomi on Monday 6th of June 2011 06:00:16 AM
Old 06-06-2011
When you call your script with a filename -or something else- as an argument, you retrieve the first argument with "$1", the second with "$2", ...
Code:
#!/bin/bash

echo "$1"

exit 0

This simple script above will give:
Code:
~$ ./this-simple-script "/path/to/file"
/path/to/file
~$

To read the file in '$1", you can simply cat "$1" but for the next requirement, write something with a loop that says:
Code:
#!/bin/bash

while read the_line; do
	echo "$the_line"
done < "$1"

exit 0

From the example you wrote, you need to read every other line
Code:
#!/bin/bash

while read the_line; do
	((i++%2)) && { echo "$the_line";}
done < "$1"

exit 0

i is a variable that's incremented (i++) on every line read.
i%2 returns 1 or 0, depending i is odd or even, basically, it returns 0 when i is 2; 4; 6; ...
And in sh/bash and many others scripting languages; zero means no errors.
No Errors: execute what's after the &&, so echo "$the_line"

Long talk, heh? Smilie
Last edited by tukuyomi; 06-06-2011 at 07:05 AM..
 

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LEARN ABOUT CENTOS

locale::codes::script

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

NAME

       Locale::Codes::Script - standard codes for script identification

SYNOPSIS

	  use Locale::Codes::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::Codes::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. 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:

	  $script = code2script('phnx','alpha');
	  $script = code2script('phnx',LOCALE_SCRIPT_ALPHA);

       The codesets currently supported are:

       alpha, LOCALE_SCRIPT_ALPHA
	   This is a set of four-letter (capitalized) codes from ISO 15924 such as 'Phnx' for Phoenician.  It also includes additions to this set
	   included in the IANA language registry.

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

	   This is the default code set.

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

ROUTINES

       code2script ( CODE [,CODESET] )
       script2code ( NAME [,CODESET] )
       script_code2code ( CODE ,CODESET ,CODESET2 )
       all_script_codes ( [CODESET] )
       all_script_names ( [CODESET] )
       Locale::Codes::Script::rename_script  ( CODE ,NEW_NAME [,CODESET] )
       Locale::Codes::Script::add_script  ( CODE ,NAME [,CODESET] )
       Locale::Codes::Script::delete_script  ( CODE [,CODESET] )
       Locale::Codes::Script::add_script_alias	( NAME ,NEW_NAME )
       Locale::Codes::Script::delete_script_alias  ( NAME )
       Locale::Codes::Script::rename_script_code  ( CODE ,NEW_CODE [,CODESET] )
       Locale::Codes::Script::add_script_code_alias  ( CODE ,NEW_CODE [,CODESET] )
       Locale::Codes::Script::delete_script_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.unicode.org/iso15924/
	   Home page for ISO 15924.

       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) 1997-2001 Canon Research Centre Europe (CRE).
	  Copyright (c) 2001-2010 Neil Bowers
	  Copyright (c) 2010-2013 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::Script(3)
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