AWS Lambda Echo Command: Passing Input Data to Your Function

Echo is a command in AWS Lambda that allows you to pass input data to your function. When you trigger a Lambda function, you can include data as part of the request payload, and this data will be available to your function as an argument. This is known as "echoing" the input data back to the function.

For example, if you have a Lambda function that takes a string argument, you can pass that string to the function using the `echo` command like this:
```
aws lambda invoke --function-name my-function --payload "Hello World!"
```
In this case, the `my-function` function will receive the string `"Hello World!"` as an argument when it is invoked.

The `echo` command is useful for testing purposes, as it allows you to pass input data to your function without having to write any code to retrieve the data from an external source. However, it is important to note that the `echo` command only works with the `aws lambda invoke` command, and not with other Lambda invocation methods such as API Gateway or SNS.