Terraform uses different environment variables that can be used to configure various aspects of how Terraform behaves. this section documents those variables, their potential values, and how to use them.
If set to any value, enables detailed logs to appear on stderr which is useful for debugging. For example:
```shell
export TF_LOG=TRACE
```
To disable, either unset it or set it to empty. When unset, logging will default to stderr. For example:
```shell
export TF_LOG=
```
For more on debugging Terraform, check out the section on [Debugging](/docs/internals/debugging.html).
## TF_LOG_PATH
This specifies where the log should persist its output to. Note that even when `TF_LOG_PATH` is set, `TF_LOG` must be set in order for any logging to be enabled. For example, to always write the log to the directory you're currently running terraform from:
```shell
export TF_LOG_PATH=./terraform.log
```
For more on debugging Terraform, check out the section on [Debugging](/docs/internals/debugging.html).
## TF_INPUT
If set to "false" or "0", causes terraform commands to behave as if the `-input=false` flag was specified. This is used when you want to disable prompts for variables that haven't had their values specified. For example:
```shell
export TF_INPUT=0
```
## TF_MODULE_DEPTH
When given a value, causes terraform commands to behave as if the `-module-depth=VALUE` flag was specified. By setting this to 0, for example, you enable commands such as [plan](/docs/commands/plan.html) and [graph](/docs/commands/graph.html) to display more compressed information.
```shell
export TF_MODULE_DEPTH=0
```
For more information regarding modules, check out the section on [Using Modules](/docs/modules/usage.html).
## TF_VAR_name
Environment variables can be used to set variables. The environment variables must be in the format `TF_VAR_name` and this will be checked last for a value. For example: