The terraform refresh-only command is intended to detect state file drift. This command synchronizes the state file with the actual infrastructure, updating the state to reflect any changes that have occurred outside of Terraform.
From terraform plan -refresh-only:
"Use this to detectdrift, i.e., changes made outside of Terraform."
It compares actual infrastructure to what's recorded in the state file.

The terraform import command is used to import existing infrastructure into Terraform's state. This allows Terraform to manage and destroy the imported infrastructure as part of the configuration. The terraform import command does not modify the configuration, so the imported resources must be manually added to the configuration after the import. References = [Importing Infrastructure]

Before using a remote backend in Terraform, it is mandatory to runterraform init. This command initializes a Terraform working directory, which includes configuring the backend. If aremote backend is specified, terraform initwill set up the working directory to use it, including copying any existing state to the remote backend if necessary.References= This principle is a fundamental part of working with Terraform and its backends, as outlined in general Terraform documentation and best practices. The specific HashiCorp Terraform Associate (003) study materials in the provided files did not include direct references to this information.

Terraform validate reports configuration consistency errors, such as declaring a resource identifier more than once. This means that the same resource type and name combination is used for multiple resource blocks, which is not allowed in Terraform. For example, resource "aws_instance" "example" {...} cannot be used more than once in the same configuration. Terraform validate does not report errors related to module versions, state differences, or formatting issues, as these are not relevant for checking the configuration syntax and structure. References = [Validate Configuration], [Resource Syntax]

Theterraform plancommand does not update the state file. Instead, it reads the current state and the configuration files to determine what changes would be made to bring the real-world infrastructure into the desired state defined in the configuration. The plan operation is a read-only operation and does not modify the state or the infrastructure. It is theterraform applycommand that actually applies changes and updates the state file.References= Terraform's official guidelines and documentation clarify the purpose of theterraform plancommand, highlighting its role in preparing and showing an execution plan without making any changes to the actual state or infrastructure .