What is the purpose of the Docker command 'docker-compose up'?

The command 'docker-compose up' is primarily used to start the containers that are defined in a Docker Compose file, which is typically named docker-compose.yml. This file contains the configuration for the services, networks, and volumes that your application requires.

When 'docker-compose up' is executed, Docker Compose reads the configuration file and creates the necessary services as specified, building images if they do not already exist. This results in the creation and start-up of all the containers defined under the services section of the Compose file. It also manages networking between these containers, allowing them to communicate as intended.

While it can also handle building images if needed, the primary function encompasses starting and managing the lifecycle of the containers, making them operational based on the configuration provided. Therefore, this command is essential for initializing applications composed of multiple interdependent Docker containers.