The `copy_values` processor copies values within an event and is a [mutate event]({{site.url}}{{site.baseurl}}/data-prepper/pipelines/configuration/processors/mutate-event/) processor.
| `overwrite_if_to_key_exists` | No | When set to `true`, the existing value is overwritten if `key` already exists in the event. The default value is `false`. |
Next, create a log file named `logs_json.log` and replace the `path` in the file source of your `pipeline.yaml` file with that filepath. For more information, see [Configuring Data Prepper]({{site.url}}{{site.baseurl}}/data-prepper/getting-started/#2-configuring-data-prepper).
For example, before you run the `copy_values` processor, if the `logs_json.log` file contains the following event record:
```json
{"message": "hello"}
```
When you run this processor, it parses the message into the following output: