Windows style env var.

Or this can be declared as {es_pass}.

Author: dotland

docs/reference/setup/install/check-running.asciidoc

@@ -5,7 +5,7 @@ You can test that your {es} node is running by sending an HTTPS request to port
 
 ["source","sh",subs="attributes"]
 ----
-curl --cacert {es-conf}{slash}certs{slash}http_ca.crt -u elastic:$ELASTIC_PASSWORD https://localhost:9200 <1>
+curl --cacert {es-conf}{slash}certs{slash}http_ca.crt -u elastic:%ELASTIC_PASSWORD% https://localhost:9200 <1>
 ----
 // NOTCONSOLE
 <1> Ensure that you use `https` in your call, or the request will fail.