$ curl --silent -X POST -H 'Content-Type: application/json' -d '{"jsonrpc":"2.0","method":"template.get","params":{"output":"extend","filter":{"name":"Template SNMP Device"}},"auth":"0643270e4a00986804d88ad736ad7df4","id":0}' http://localhost/api_jsonrpc.php;echo
{"jsonrpc":"2.0","result":[{"proxy_hostid":"0","host":"Template SNMP Device","status":"3","disable_until":"0","error":"","available":"0","errors_from":"0","lastaccess":"0","ipmi_authtype":"0","ipmi_privilege":"2","ipmi_username":"","ipmi_password":"","ipmi_disable_until":"0","ipmi_available":"0","snmp_disable_until":"0","snmp_available":"0","maintenanceid":"0","maintenance_status":"0","maintenance_type":"0","maintenance_from":"0","ipmi_errors_from":"0","snmp_errors_from":"0","ipmi_error":"","snmp_error":"","jmx_disable_until":"0","jmx_available":"0","jmx_errors_from":"0","jmx_error":"","name":"Template SNMP Device","flags":"0","templateid":"10066","description":"","tls_connect":"1","tls_accept":"1","tls_issuer":"","tls_subject":"","tls_psk_identity":"","tls_psk":""}],"id":0}

$ curl --silent -X POST -H 'Content-Type: application/json' -d '{"jsonrpc":"2.0","method":"template.get","params":{"output":"extend","filter":{"name":"Template SNMP Device"}},"auth":"0643270e4a00986804d88ad736ad7df4","id":0}' http://localhost/api_jsonrpc.php | jq .result[].templateid; echo
"10066"

$ curl --silent -X POST -H 'Content-Type: application/json' -d '{"jsonrpc":"2.0","method":"template.get","params":{"output":"extend","filter":{"templateid":"10066"}},"auth":"0643270e4a00986804d88ad736ad7df4","id":0}' http://localhost/api_jsonrpc.php;echo
{"jsonrpc":"2.0","result":[],"id":0}