$ yii configure/web config/main.phpIn this example, the configure command is used to configure the main.php file in the config folder of the application. The configure command will prompt the user to enter the required configuration settings for the application. Yii framework uses several package libraries to provide developers with a range of functionalities for their applications. Some of the package libraries used by Yii framework include: 1. Yii2 Basic Project Template - a package library that provides a basic project template for developers to start building applications. 2. Gii - a package library that provides a code generator for developers to generate model, view and controller files. 3. RBAC - a package library that provides role-based access control for developers to manage access to their applications. In conclusion, Yii configure is a useful tool in Yii framework that helps developers to configure their applications easily without the need for manual editing of configuration files. The framework also provides several package libraries that help developers to build robust and feature-rich applications.