aws-cliの標準出力をjqで整形 ref: http://qiita.com/okisanjp/items/52bbcd7bb751f7ab5174

file0.txt

$ aws ec2 describe-instances

{
    "Reservations": [
        {
            "OwnerId": "xxxxxxxxxxx", 
            "ReservationId": "r-xxxxxxx", 
            "Groups": [], 
            "Instances": [
                {
                    "Monitoring": {
                        "State": "disabled"
                    }, 
                    "PublicDnsName": "", 
                    "State": {
                        "Code": 16, 
                        "Name": "running"
                    }, 

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                    "Architecture": "x86_64", 
                    "RootDeviceType": "ebs", 
                    "RootDeviceName": "/dev/xvda", 
                    "VirtualizationType": "hvm", 
                    "Tags": [
                        {
                            "Value": "example.com", 
                            "Key": "Name"
                        }
                    ], 
                    "AmiLaunchIndex": 0
                }
            ]
        }
    ]
}

file1.txt

$ brew install jq
==> Downloading https://homebrew.bintray.com/bottles/jq-1.4.yosemite.bottle.tar.gz
######################################################################## 100.0%
==> Pouring jq-1.4.yosemite.bottle.tar.gz

file2.txt

$ aws ec2 describe-instances | jq '.Reservations[].Instances[].Tags[]'

{
  "Value": "app.example.com",
  "Key": "Name"
}
{
  "Value": "db.example.com",
  "Key": "Name"
}
{
  "Value": "elasticsearch.example.com",
  "Key": "Name"
}
{
  "Value": "example.com",
  "Key": "Name"
}

file3.txt

$ aws ec2 describe-instances | jq '.Reservations[].Instances[].Tags[].Value'

"app.example.com"
"db.example.com"
"elasticsearch.example.com"
"example.com"

file4.txt

$ aws ec2 describe-instances | jq -r '.Reservations[].Instances[] | .PrivateIpAddress + "\t" + .Tags[].Value'

192.168.1.125   app.example.com
192.168.1.14    db.example.com
192.168.1.250   elasticsearch.example.com
192.168.1.230   example.com

file5.txt

$ aws ec2 describe-instances | jq '.Reservations[].Instances[].NetworkInterfaces[].Groups[]'

  "GroupName": "web server",
  "GroupId": "sg-d5e80ow8"
}
{
  "GroupName": "WordPress powered by AMIMOTO -HVM--Version- 1-1-AutogenByAWSMP-1",
  "GroupId": "sg-7dc54320"
}
{
  "GroupName": "streamdata",
  "GroupId": "sg-d5es4rd3"
}
{
  "GroupName": "db",
  "GroupId": "sg-d5e8fd83y"
}

file6.txt

$ aws ec2 describe-instances | jq -c '.Reservations[].Instances[].NetworkInterfaces[].Groups[]'

{"GroupName":"web server","GroupId":"sg-d5e80ow8"}
{"GroupName":"WordPress powered by AMIMOTO -HVM--Version- 1-1-AutogenByAWSMP-1","GroupId":"sg-7dc54320"}
{"GroupName":"streamdata","GroupId":"sg-d5es4rd3"}
{"GroupName":"db","GroupId":"sg-d5e8fd83y"}

file7.txt

$ aws ec2 describe-instances | jq -M '.Reservations[].Instances[].NetworkInterfaces[].Groups[]'

  "GroupName": "web server",
  "GroupId": "sg-d5e80ow8"
}
{
  "GroupName": "WordPress powered by AMIMOTO -HVM--Version- 1-1-AutogenByAWSMP-1",
  "GroupId": "sg-7dc54320"
}
{
  "GroupName": "streamdata",
  "GroupId": "sg-d5es4rd3"
}
{
  "GroupName": "db",
  "GroupId": "sg-d5e8fd83y"
}

file8.txt

$ aws ec2 describe-instances | jq '.Reservations[].Instances[].NetworkInterfaces[].Groups[] | select(.GroupName == "web server")'

{
  "GroupName": "web server",
  "GroupId": "sg-d5e80ow8"
}

file9.txt

$ aws ec2 describe-instances | jq -r -c '.Reservations[].Instances[] | select(.NetworkInterfaces[].Groups[].GroupName == "web server") | .PrivateIpAddress + "\t" + .Tags[].Value'

192.168.1.230   example.com