curl -XGET 'localhost:9200'
{
  "name" : "THbbezM",
  "cluster_name" : "elasticsearch",
  "cluster_uuid" : "CtYdgNUzQrS5YRTRT7xNJw",
  "version" : {
    "number" : "5.5.0",
    "build_hash" : "260387d",
    "build_date" : "2017-06-30T23:16:05.735Z",
    "build_snapshot" : false,
    "lucene_version" : "6.6.0"
  },
  "tagline" : "You Know, for Search"
}