What does the command 'terraform fmt' do when executed without flags in a directory with configuration files?

The command 'terraform fmt' is designed to rewrite Terraform configuration files into a canonical format and style. When this command is executed without any flags, it scans the directory for files ending in .tf or .tf.json and automatically reformats them to adhere to the standard conventions recommended by Terraform. This helps ensure that the code is consistent and more readable across the board, which is especially important in collaborative environments where multiple users may be editing the same files.

Reformatting includes changes to indentation, spacing, and other stylistic elements that do not affect the actual functionality of the configuration. The goal is to promote best practices in coding by ensuring uniformity in formatting, which can help developers quickly identify issues and understand the code structure.

In contrast, other choices do not accurately reflect the function of 'terraform fmt'. For instance, while checking formatting or validating files is important, that specific functionality is not what 'terraform fmt' does by default when executed without flags. Instead, its primary role is to perform automatic formatting adjustments to maintain best practices in code styling.