Updated Utilize multiple DNS API keys (markdown)

Utilize-multiple-DNS-API-keys.md

@@ -1,3 +1,39 @@
 # How to utilize multiple DNS API keys
 
+As for now, the dns api key/secret is saved in the global `account.conf` file, so that it can be reused for any of the domains in your account.
+
+So, what if you have multiple dns api keys.  The key point is to use multiple `account.conf` file.
+
+You can use either of the following ways:
+
+## 2. Use muitlple linux users to install and use acme.sh
+
+It's the easiest way to use.  You can just create multiple Linux users, and install and use acme.sh for each users:
+
+```
+su  acmeuser1
+
+curl https://get.acme.sh | sh -s email=my@example.com
+
+source ~/.acme.sh/acme.sh.env
+
+export MYDNS_APIKey1=xxxxxxx
+
+acme.sh --issue -d domain1.com --dns ........
+```
+
+And then switch to another user:
+
+```
+su  acmeuser2
+
+curl https://get.acme.sh | sh -s email=my@example.com
+
+source ~/.acme.sh/acme.sh.env
+
+export MYDNS_APIKey2=xxxxxxx
+
+acme.sh --issue -d domain1.com --dns ........
+```
+