Every application is the combination of code and a set of configuration that

dictates how that code should function. The configuration may define the

databasebeing used, if something should be cached or how verbose

thesame codebase can be run using multiple different configurations. For

example, the ``dev`` environment should use configuration that makes development

optimized for speed.

dictates how that code should function. The configuration may define the database

being used, if something should be cached or how verbose logging should be.

In Symfony,theidea of "environments" is the idea that the same codebase can be

run using multiple different configurations. Forexample, the ``dev`` environment

``prod`` environment should use a set of configurationoptimized for speed.

..index::

single: Environments; Configuration files