# join

The `join` step type combines strings into a single value, a building block for assembling arguments, lists, or messages that later steps in your custom commands and workflows consume.

```yaml
steps:
  - name: targets
    type: join
    separator: ","
    options:
      - vpc
      - eks
      - rds
```

## Fields

- **`options`**
  Array of strings to resolve and join.
- **`separator`**
  Optional separator. Defaults to a newline.
- **`content`**
  Alternative single template source. When set, Atmos resolves and returns it as-is.

Provide either `options` or `content`.