curl HTTP_USER_AGENT
[root@bigdata-server-01 ~]# curl 13.26.92.20
array(27) {
  ["HTTP_USER_AGENT"]=>
  string(11) "curl/7.29.0"
  ["HTTP_HOST"]=>
[root@bigdata-server-01 ~]# curl 13.26.92.20
array(27) {
  ["HTTP_USER_AGENT"]=>
  string(11) "curl/7.29.0"
  ["HTTP_HOST"]=>