Trying to extract values from aws-cli response using jq but failing, what am I doing wrong?

Question

I have the following json structure:

[
  {
    "IsDefault": false,
    "CidrBlock": "172.19.0.0/16",
    "DhcpOptionsId": "dopt-37fd70550",
    "State": "available",
    "CidrBlockAssociationSet": [
      {
        "CidrBlockState": {
          "State": "associated"
        },
        "CidrBlock": "172.19.0.0/16",
        "AssociationId": "vpc-cidr-assoc-f3c1559a"
      }
    ],
    "Tags": [
      {
        "Key": "Name",
        "Value": "product-Production"
      }
    ],
    "InstanceTenancy": "default",
    "VpcId": "vpc-1f0e197d"
  },
  {
    "IsDefault": false,
    "CidrBlock": "10.0.0.0/16",
    "DhcpOptionsId": "dopt-0a550861",
    "State": "available",
    "CidrBlockAssociationSet": [
      {
        "CidrBlockState": {
          "State": "associated"
        },
        "CidrBlock": "10.0.0.0/16",
        "AssociationId": "vpc-cidr-assoc-8955dae0"
      }
    ],
    "Tags": [
      {
        "Key": "Name",
        "Value": "Marketing VPC"
      }
    ],
    "InstanceTenancy": "default",
    "VpcId": "vpc-36b5585d"
  },
  .
  .
  .
]

I'm trying to print all VpcId's using jq but I can't find the right way to do it.

Here's what I've tried:

command | jq -r '.VpcId[]'
command | jq -r '.VpcId'
command | jq -r '.[] | .VpcId'

What am I doing wrong?

Your third effort works for me, although I have to use double quotes since I'm on Windows. What is the error you get for `.[] | .VpcId`? — Mike Patrick, Aug 05 '18 at 17:45

score 2 · Accepted Answer · answered Aug 05 '18 at 18:12

It looks like the command you are using is aws ec2 describe-vpcs.

This command actually returns the following structure:

{
    "Vpcs": [
        {
            "VpcId": "vpc-xxxxxxxx", 
        }
    ]
}

So you want to reach into the Vpcs key before you iterate over the array, Like this:

aws ec2 describe-vpcs | jq -r '.Vpcs | .[] | .VpcId'

score 0 · Answer 2 · answered Aug 05 '18 at 19:16

0

An alternative to consider would be to use .., e.g.

.. | .VpcId? // empty

will print the values of all "VpcId" keys, except for null and false values.

Incidentally, .Vpcs | .[] | .VpcId can be abbreviated to .Vpcs[].VpcId

answered Aug 05 '18 at 19:16

peak

105,803
17
152
177

Trying to extract values from aws-cli response using jq but failing, what am I doing wrong?

2 Answers2