Yii has full featured support for console applications, whose structure is very similar to a Yii web application. A console application
consists of one or more [[yii\console\Controller]] classes, which are often referred to as "commands" in the console environment. Each controller can also have one or more actions, just like web controllers.
The console application entry script is equivalent to the `index.php` bootstrap file used for the web application. The console entry script is typically called `yii`, and located in your application's root directory. The contents of the console application entry script contains
This script will be created as part of your application; you're free to edit it to suit your needs. The `YII_DEBUG` constant can be set `false` if you do
not want to see a stack trace on error, and/or if you want to improve the overall performance. In both basic and advanced application
templates, the console application entry script has debugging enabled to provide a more developer-friendly environment.
If your web application and the console application share a lot of configuration parameters and values, you may consider moving the common
parts into a separate file, and including this file in both of the application configurations (web and console). You can see an example of this in the "advanced" application template.
test databases, which are configured in each individual test suite. To do change the configuration dynamically, simply specify a custom application configuration
file via the `appconfig` option when executing the command:
you define one or more actions that correspond to sub-commands of the controller. Within each action, you write code that implements the appropriate tasks for that particular sub-command.
corresponds to the second, and so on. If not enough arguments are provided when the command is called, the corresponding parameters
will take the declared default values, if defined. If no default value is set, and no value is provided at runtime, the command will exit with an error.
Using exit codes is a best practice for console application development. Conventionally, a command returns `0` to indicate that
everything is OK. If the command returns a number greater than zero, that's considered to be indicative of an error. The number returned will be the error
code, potentially usable to find out details about the error.
For example `1` could stand generally for an unknown error and all codes above would be reserved for specific cases: input errors, missing files, and so forth.