> For the complete documentation index, see [llms.txt](https://docs.fluentbit.io/manual/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.fluentbit.io/manual/4.1/data-pipeline/processors/filters.md).

# Filters as processors

You can use any [filter](/manual/4.1/data-pipeline/filters.md) as a processor in Fluent Bit.

{% hint style="info" %}
Only [YAML configuration files](/manual/4.1/administration/configuring-fluent-bit/yaml.md) support processors.
{% endhint %}

## Grep example

In this example, the [Grep](/manual/4.1/data-pipeline/filters/grep.md) filter is an output processor that sends log records only if they match a specified regular expression.

{% tabs %}
{% tab title="fluent-bit.yaml" %}

```yaml
pipeline:
  inputs:
    - name: tail
      path: lines.txt
      parser: json

  outputs:
    - name: stdout
      match: '*'

      processors:
        logs:
          - name: grep
            regex: log aa
```

{% endtab %}
{% endtabs %}


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