A fancy jq filter to turn JSON output into a CSV format

jq-json-to-csv.sh

# From the second answer here - this SO answer gets all the credit:  
# https://stackoverflow.com/questions/32960857/how-to-convert-arbitrary-simple-json-to-csv-using-jq

# This is the filter to convert JSON to CSV output:
# NOTE:  This filter only works on "flat" JSON; nested properties don't work with this filter as-is.
jq -r '(.[0] | keys_unsorted) as $keys | ([$keys] + map([.[ $keys[] ]])) [] | @csv'

# For example:
aws ec2 describe-instances \
  --region us-west-2 \
  --query 'Reservations[].Instances[].{ commonName: Tags[?Key == `Name`]|[0].Value, instanceId: InstanceId, privateIp: PrivateIpAddress, publicIp: PublicIpAddress, zone: Placement.AvailabilityZone, status: State.Name, startedAt: LaunchTime, keyPair: KeyName }' \
  --output json \
  | jq -r '(.[0] | keys_unsorted) as $keys | ([$keys] + map([.[ $keys[] ]])) [] | @csv'