Contents

Displays code diff of the generated CloudFormation template locally vs the existing template on AWS. You can set a desired diff viewer by setting the `LONO_DIFF` environment variable.

## Examples

    lono cfn diff my-stack

The output should look similiar to this:

<img src="/img/tutorials/ec2/cfn-update-instance-type.png" alt="Stack Update" class="doc-photo">

Notice that before the update gets performed lono provides a preview of the changes that are about to take place. There are two types of "diffs" in the preview.

1. Source code diff of the templates. This is generated by downloading the current CloudFormation template and comparing it with the locally generated one using `colordiff`.
2. CloudFormation Change Set list of changes. This is generated using [AWS CloudFormation Change Set](https://medium.com/boltops/a-simple-introduction-to-cloudformation-part-4-change-sets-dry-run-mode-c14e41dfeab7) feature.

Version data entries

3 entries across 3 versions & 1 rubygems

Version	Path
lono-4.0.3	lib/lono/help/cfn/diff.md
lono-4.0.2	lib/lono/help/cfn/diff.md
lono-4.0.1	lib/lono/help/cfn/diff.md