What does the `terraform apply` command do?

The terraform apply command is a critical operation in Terraform's workflow. When executed, it applies the changes that you have defined in your configuration files to the managed infrastructure. This involves creating new resources, modifying existing ones, or destroying resources as specified by the planned changes.

By using the apply command, you are essentially instructing Terraform to take the current state of your infrastructure, evaluate it against the desired state outlined in your configuration, and make any necessary adjustments to synchronize the two. This includes actions like provisioning new virtual machines, updating a load balancer, or removing obsolete resources.

Other options describe functionalities that are not covered by terraform apply. For example, showing what will happen if the apply is executed is the function of the terraform plan command, which allows users to review the potential changes before they are made. Removing resources is done through specific commands like terraform destroy, and preparing the working directory is related to initial setup processes rather than the application of changes post-configuration. Therefore, the primary role of terraform apply rests in executing the infrastructure changes based on the definitions provided in the configuration files.