Write and modify Terraform configuration from the CLI

This topic provides an overview of the Terraform CLI commands you can use to develop, format, and validate your Terraform configuration.

Introduction

The Terraform language is Terraform's primary user interface, and all of Terraform's workflows rely on configurations written in the Terraform language.

Workflows

Terraform CLI includes several commands to make Terraform code more convenient to work with. You can integrate the following commands into your editing workflow to test expressions and format and validate your configuration syntax:

The terraform console command starts an interactive shell for evaluating Terraform expressions, to quickly verify that a particular resource argument results in the value you expect.
The terraform fmt command automatically rewrites Terraform configuration files to a canonical format and style, so you don't have to waste time making minor adjustments for readability and consistency. The terraform fmt command works well as a pre-commit hook in your version control system.
The terraform validate commands validates the syntax and arguments of the Terraform configuration files in a directory, including argument and attribute names and types for resources and modules. The plan and apply commands automatically validate a configuration before performing any other work. Running validate isn't a crucial part of the core workflow but can be very useful as a pre-commit hook or as part of a continuous integration pipeline.
The 0.13upgrade and 0.12upgrade commands modify the configuration files in a Terraform module automatically to help deal with major syntax changes that occurred in the 0.13 and 0.12 releases of Terraform. Both commands are only available in the Terraform version they are associated with. Make sure to upgrade older code to be compatible with 0.12 before attempting to make it compatible with 0.13. For more detailed information about updating code for new Terraform versions, refer to the upgrade guides.