---
name: "config_data"
section: "1p"
platform: "linux"
package: "perl-module-build"
version: "0.4234-6"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/config_data/1p"
---

# config\_data(1p)

Query or change configuration of Perl modules

## 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 `"config_data"` 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 (`"CPAN::Config"`), Jon Swartz (`"HTML::Mason::Config"`), Andy Wardley (`"Template::Config"`), and Larry Wall (perl's own Config.pm) have developed independently.

The configuration system employed here was developed in the context of `"Module::Build"`.  Under this system, configuration information for a module `"Foo"`, for example, is stored in a module called `"Foo::ConfigData"`) (I would have called it `"Foo::Config"`, but that was taken by all those other systems mentioned in the previous paragraph...).  These `"...::ConfigData"` modules contain the configuration data, as well as publicly accessible methods for querying and setting (yes, actually re-writing) the configuration data.  The `"config_data"` 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 `"config"` values and `"feature"` values.  A `"config"` value may be any perl scalar, including references to complex data structures.  It must, however, be serializable using `"Data::Dumper"`.  A `"feature"` 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 `"config"` or `"feature"` values.  The following options are supported:

- module

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

- feature

  When passed the name of a `"feature"`, 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 `"config"` entry, shows its value.  The value will be displayed using `"Data::Dumper"` (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 `"feature"` to the given boolean value.  Specify the value as either 1 or 0.

- set\_config

  Sets the given `"config"` entry to the given value.

- eval

  If the `"--eval"` option is used, the values in `"set_config"` 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

  Prints a help message, including a few examples, and exits.

## AUTHOR

Ken Williams, kwilliams@cpan.org

## COPYRIGHT

Copyright (c) 1999, Ken Williams.  All rights reserved.

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

## SEE ALSO

**Module::Build**(3), [**perl**(1)](/perl/1.md).