One of the biggest pains with terraform is that it's not totally 12-factor compliant (III. Config). That is, terraform doesn't consume environment variables for all settings & parameters. As a result, many of us use wrappers like terragrunt to invoke terraform.
Have you ever wanted to set the backend config using strictly environment variables?
Well, as it turns out this is possible - just in an extremely roundabout way. For example, if we want to set the backend-config bucket using an environment variable, we can do the following:
export TF_CLI_ARGS_init="-backend-config=bucket=my-bucket"