如何使用jq‘筛选一个值

Question

我正在编写一个脚本来自动创建AWS卷。我正在尝试使用echo和jq过滤出volumeId的值

[root@ip-172-41-23-8 ~]# aws ec2 describe-volumes --filters Name=status,Values=available Name=availability-zone,Values=us-east-1d  Name=tag:Name,Values=*USEPROD*|jq ".VolumeId"
null
[root@ip-172-41-23-8 ~]# echo $value | jq
{
  "Volumes": [
    {
      "AvailabilityZone": "us-east-1d",
      "Attachments": [],
      "Tags": [
        {
          "Value": "Dev",
          "Key": "Env"
        },
        {
          "Value": "Shell",
          "Key": "Deployment"
        },
        {
          "Value": "cnx30au - Kafka-Data-Node - /dev/sdg - /abc/data/sda",
          "Key": "Name"
        }
      ],
      "Encrypted": true,
      "VolumeType": "gp2",
      "VolumeId": "vol-095ac513f0f049ba5",
      "State": "available",
      "KmsKeyId": "arn:aws:kms:us-east-1:709721360603:key/xvfgfr-dsdsd-dsdsds-a00c-dsdsdsd34dsd",
      "SnapshotId": "",
      "Iops": 100,
      "CreateTime": "2019-04-08T21:52:31.473Z",
      "Size": 10
    }
  ]
}


json="aws ec2 describe-volumes --filters Name=status,Values=available Name=availability-zone,Values=us-east-1d  Name=tag:Name,Values=*USEPROD*"
echo "Executing: ${json}"
value=`${json}`
valueid=`echo ${value}|jq '.VolumeId'`
[root@ip-172-31-87-1 ~]# echo $valueid
null

在筛选可用卷时，我只希望输出如下所示

vol-095ac513f0f049ba5

Answer 1

VolumeId嵌套了两次，您需要在查询中标识这一点

valueid=`echo ${value} | jq '.[]|.[]|.VolumeId'`

Answer 2

或者简单地说：

jq '.Volumes[].VolumeId'