The cfn-summary command provides an overview of a CloudFormation json templates contents.
$ cfn-summary templates/web-app.json
Conditions has 2 resources
Mappings has 1 resources
Outputs has 2 resources
Parameters has 20 resources
Resources has 10 resources
You can also specify sections to summarise. In this example we check the number of inputs and outputs for a stack.
$ cfn-summary templates/web-app.json parameters,outputs
Outputs has 2 resources
Parameters has 20 resources