Exporting and Importing Configuration
Drush provides commands to export, transfer, and import configuration files to and from a Drupal 8 site. Configuration can be altered by different methods in order to provide different behaviors in different environments; for example, a development server might be configured slightly differently than the production server.
This document describes how to make simple value changes to configuration based on the environment, how to have a different set of enabled modules in different configurations without affecting your exported configuration values, and how to make more complex changes.
Simple Value Changes
It is not necessary to alter the configuration system values to make simple value changes to configuration variables, as this may be done by the configuration override system.
The configuration override system allows you to change configuration values for a given instance of a site (e.g. the development server) by setting configuration variables in the site's settings.php file. For example, to change the name of a local development site:
$config['system.site']['name'] = 'Local Install of Awesome Widgets, Inc.';
Note that the configuration override system is a Drupal feature, not a Drush feature. It should be the preferred method for changing configuration values on a per-environment basis; however, it does not work for some things, such as enabling and disabling modules.
See Config Split for advanced variation by environment.