# config-nunjucks-custom-filters (Nunjucks Custom Filters) You can run this example with: ```bash npx promptfoo@latest init --example config-nunjucks-custom-filters cd config-nunjucks-custom-filters ``` ## Usage This example is pre-configured in `promptfooconfig.yaml`. That means you can just run: ```bash promptfoo eval ``` `allcaps.js` is a standard [Nunjucks custom filter](https://mozilla.github.io/nunjucks/api.html#custom-filters).