gistfile1.txt

{
  "category": "a6ad5d40-c411-4191-b286-a55114d68bc2",
  "enabled": true,
  "dynamic": false,
  "nodeIds": [],
  "query": {
    "where": [
      {
        "value": "Linux",
        "comparator": "eq",
        "attribute": "OS",
        "objectType": "node"
      }
    ],
    "composition": "And",
    "select": "node"
  },
  "description": "",
  "displayName": "api group"
}

curl -k  -X PUT -H "X-API-Token : dTxvl4eL8p3YqvwefVbaJLdy8DyEt7Vw" -H "content-type: application/json" https://myRudder.com/rudder/api/latest/groups -d @groups.json