I have a string like below:

```
downCircuit received;TOKENS START;{"action":'"UPDATE","device_id":"CP0027829","link_index":"101","name":"uplink101","description":"link1-0/0/3","priority":"200","status":"DOWN","wan_status":"DOWN","vlan":"4094","vlan_description":"vlan4094-intf","topic":"uplinks","stream_timestamp":"1547015547","aws_host":"attwifi-poc-central.arubathena.com","aws_timestamp":"1547015547","customer_id":"6666778917"};TOKENS END

```

I wanted to extract the value of link\_index from it. i.e. output should be 101 in this case. Can somebody please help on how to extract 101 from my string.