### [Read this on the main serverless docs site](https://www.serverless.com/framework/docs/guides/variables/cli-options) # Reference CLI Options To reference CLI options that you passed, use the `${opt:}` syntax in your `serverless.yml` configuration file. It is valid to use the empty string in place of ``. This looks like "`${opt:}`" and the result of declaring this in your `serverless.yml` is to embed the complete `options` object (i.e. all the command line options from your `serverless` command). ```yml service: new-service provider: aws functions: hello: name: ${opt:stage}-hello handler: handler.hello world: name: ${opt:stage}-world handler: handler.world ``` In the above example, you're dynamically adding a prefix to the function names by referencing the `stage` option that you pass in the CLI when you run `serverless deploy --stage dev`. So when you deploy, the function name will always include the stage you're deploying to.