How to export environment variables from a Lambda function.

As referred in this documentation, you can obtain all the configuration details for the function through the AWS CLI like this:

aws lambda get-function-configuration --function-name <value> --output json

You can use the output to update the new function using this command:

aws lambda update-function-configuration --function-name <value> --cli-input-json <output from previous command>

You may need to change the output as needed before using it for the update-function-configuration invocation.