---
name: external
description: |
  Discover external dependencies from initial results.
type: boolean
env:
  - TG_EXTERNAL
---

import { Aside } from '@astrojs/starlight/components';

Controls whether Terragrunt should discover and include external dependencies in the list results. External dependencies are Terragrunt configurations that are referenced by your configurations but exist outside the current working directory.

This flag is most useful when:
- Investigating the complete dependency graph of your infrastructure
- Determining the full blast radius of a change

Example:

```bash
$ terragrunt list -l --dependencies
Type  Path          Dependencies
unit  a-dependent   b-dependency
unit  b-dependency
```

```bash
$ terragrunt list -l --dependencies --external
Type  Path                      Dependencies
unit  ../external/c-dependency
unit  a-dependent               ../external/c-dependency, b-dependency
unit  b-dependency
```

<Aside type="note">
  The `--external` flag is typically used in combination with `--dependencies` to show why the external dependency was discovered.
</Aside>
