redirection in unix, '<' as opposed to '>' Post: 302112002

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Top Forums UNIX for Dummies Questions & Answers redirection in unix, '<' as opposed to '>' Post 302112002 by cfajohnson on Saturday 24th of March 2007 12:24:46 AM

Old

03-24-2007

Registered User

Quote:

Originally Posted by alikun

Greetings,

When directing in unix, symbol > means saving. E.g. I can save ls command output into mama like this:

ls -f > mama

Could someone give me a real example of how the opposite, i.e. symbol < is used?. Could not find its counterpart in Windows (I seem to learn better when i see unix's counterparts in windows upon which i depended for ages)

Code:
## Read first line from file:
read line < FILENAME
If the line contained leading or trailing spaces, they would be lost with that command. To prevent that, the internal field separator is cleared:
Code:
IFS="" read line < FILENAME
If there are any backslashes in the line, they will be removed and the literal character following will be used. If the last character on the line is a backslash, read will continue reading the next line.

To disable backslash escaping, use the -r option:
Code:
IFS="" read -r line < FILENAME
To read an entire file (if the file is long, sed or awk may be a better tool to use):
Code:
while IFS="" read -r line
do
    ## Do something with the line here
done < FILENAME
The input of other commands can also be redirected from a file. For example, to change all uppercase As to Zs:
Code:
tr A Z < FILENAME

cfajohnson

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locale::codes::langfam

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) 2011-2012 Sullivan Beck

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

perl v5.16.2							    2012-10-11					       Locale::Codes::LangFam(3pm)