JavaScript Object Notation (JSON) (http://json.org/), a standard, machine- and human-readable information interchange format. Here's what the AZs in the us-east-1 (North Virginia) region look like represented as JSON:
aws ec2 describe-availability-zones --output json { "AvailabilityZones": [ { "State": "available", "RegionName": "us-east-1", "Messages": [], "ZoneName": "us-east-1a" }, { "State": "available", "RegionName": "us-east-1", "Messages": [], "ZoneName": "us-east-1c" }, { "State": "available", "RegionName": "us-east-1", "Messages": [], "ZoneName": "us-east-1d" }, { "State": "available", "RegionName": "us-east-1", "Messages": [], "ZoneName": "us-east-1e" } ] }