Which command lets you experiment with Terraform's built-in functions?

The command that allows you to experiment with Terraform's built-in functions is the Terraform console. This interactive console provides a REPL (Read-Eval-Print Loop) environment where users can input Terraform expressions and evaluate them in real-time. It is particularly useful for testing out functions, understanding how they work, and seeing the results immediately without the need to create and apply Terraform configuration files.

Using the console, you can directly query Terraform's built-in functions, manipulate variables, and experiment with expressions, which is essential for getting a hands-on understanding of how different functionalities work in Terraform. This feature is advantageous for users who want to learn and explore Terraform syntax and capabilities without impacting their infrastructure.

Other commands, such as applying changes or planning deployments, serve different purposes. For instance, applying changes updates infrastructure, while planning previews proposed changes. Validation checks the syntax and configuration correctness but does not offer an interactive environment for function experimentation.