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CONFIG_DATA

Section: Perl Programmers Reference Guide (1)

Updated: 2016-01-15

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NAME

config_data - Query or change configuration of Perl modules

SYNOPSIS

  # Get config/feature values
  config_data --module Foo::Bar --feature bazzable
  config_data --module Foo::Bar --config magic_number

  # Set config/feature values
  config_data --module Foo::Bar --set_feature bazzable=1
  config_data --module Foo::Bar --set_config magic_number=42

  # Print a usage message
  config_data --help

DESCRIPTION

The

 &quot;config_data&quot;

tool provides a command-line interface to the configuration of Perl modules. By ``configuration, we mean something akin to ``user preferences or ``local settings''. This is a formalization and abstraction of the systems that people like Andreas Koenig (

 &quot;CPAN::Config&quot;

), Jon Swartz (

 &quot;HTML::Mason::Config&quot;

), Andy Wardley (

 &quot;Template::Config&quot;

), and Larry Wall (perl's own Config.pm) have developed independently.

The configuration system employed here was developed in the context of

 &quot;Module::Build&quot;

. Under this system, configuration information for a module

 &quot;Foo&quot;

, for example, is stored in a module called

 &quot;Foo::ConfigData&quot;

) (I would have called it

 &quot;Foo::Config&quot;

, but that was taken by all those other systems mentioned in the previous paragraph...). These

 &quot;...::ConfigData&quot;

modules contain the configuration data, as well as publicly accessible methods for querying and setting (yes, actually re-writing) the configuration data. The

 &quot;config_data&quot;

script (whose docs you are currently reading) is merely a front-end for those methods. If you wish, you may create alternate front-ends.

The two types of data that may be stored are called

 &quot;config&quot;

values and

 &quot;feature&quot;

values. A

 &quot;config&quot;

value may be any perl scalar, including references to complex data structures. It must, however, be serializable using

 &quot;Data::Dumper&quot;

. A

 &quot;feature&quot;

is a boolean (1 or 0) value.

USAGE

This script functions as a basic getter/setter wrapper around the configuration of a single module. On the command line, specify which module's configuration you're interested in, and pass options to get or set

 &quot;config&quot;

 &quot;feature&quot;

values. The following options are supported:

module

Specifies the name of the module to configure (required).:

feature

When passed the name of a

 &quot;feature&quot;

, shows its value. The value will be 1 if the feature is enabled, 0 if the feature is not enabled, or empty if the feature is unknown. When no feature name is supplied, the names and values of all known features will be shown.:

config

When passed the name of a

 &quot;config&quot;

entry, shows its value. The value will be displayed using

 &quot;Data::Dumper&quot;

(or similar) as perl code. When no config name is supplied, the names and values of all known config entries will be shown.:

set_feature

Sets the given

 &quot;feature&quot;

to the given boolean value. Specify the value as either 1 or 0.:

set_config

Sets the given

 &quot;config&quot;

entry to the given value.:

eval

If the

 &quot;--eval&quot;

option is used, the values in

 &quot;set_config&quot;

will be evaluated as perl code before being stored. This allows moderately complicated data structures to be stored. For really complicated structures, you probably shouldn't use this command-line interface, just use the Perl API instead.:

help