Fixed some errors in the explanation

Author: javiereguiluz

cookbook/configuration/environments.rst

@@ -223,21 +223,21 @@ debug mode enabled. Use ``--env`` and ``-no-debug`` options to modify this behav
     # 'dev' environment and debug enabled
     $ php app/console command_name
 
-    # 'prod' environment and debug enabled
+    # 'prod' environment (debug is always disabled for 'prod')
     $ php app/console command_name --env=prod
 
-    # 'prod' environment and debug disabled
-    $ php app/console command_name --env=prod --no-debug
+    # 'test' environment and debug disabled
+    $ php app/console command_name --env=test --no-debug
 
 In addition to ``--env`` and ``--debug`` options, Symfony commands behavior can
 also be controlled with environment variables. The Symfony console application
 checks the existence and value of these environment variables before executing
 any command:
 
 * ``SYMFONY_ENV``, sets the execution environment of the command to the value of
-  this variable.
-* ``SYMFONY_DEBUG``, if ``true``, debug mode is enabled for the command. If
-  ``false``, debug mode is disabled.
+  this variable (``dev``, ``prod``, ``test``, etc.)
+* ``SYMFONY_DEBUG``, if ``0``, debug mode is disabled. Otherwise, debug mode is
+  enabled.
 
 These environment variables are very useful for production servers, because they
 allow you to ensure that commands are always run on ``prod`` environment without