use printf to replace printenv

Signed-off-by: Weiping Cai <weiping.cai@daocloud.io>

content/en/docs/tasks/inject-data-application/define-interdependent-environment-variables.md

@@ -53,12 +53,10 @@ Pod:
     kubectl logs pod/dependent-envars-demo
     ```
     ```
-    SERVICE_ADDRESS
+
-    https://172.17.0.1:80
+    UNCHANGED_REFERENCE=$(PROTOCOL)://172.17.0.1:80
-    UNCHANGED_REFERENCE
+    SERVICE_ADDRESS=https://172.17.0.1:80
-    $(PROTOCOL)://172.17.0.1:80
+    ESCAPED_REFERENCE=$(PROTOCOL)://172.17.0.1:80
-    ESCAPED_REFERENCE
-    $(PROTOCOL)://172.17.0.1:80
     ```
 
 As shown above, you have defined the correct dependency reference of `SERVICE_ADDRESS`, bad dependency reference of `UNCHANGED_REFERENCE` and skip dependent references of `ESCAPED_REFERENCE`.

content/en/examples/pods/inject/dependent-envars.yaml

@@ -6,7 +6,7 @@ spec:
   containers:
     - name: dependent-envars-demo
       args:
-    - while true; do echo -en '\n'; echo SERVICE_ADDRESS;printenv SERVICE_ADDRESS;echo UNCHANGE_REFERENCE;printenv UNCHANGE_REFERENCE;echo ESCAPED_REFERENCE;printenv ESCAPED_REFERENCE; sleep 30; done;
+        - while true; do echo -en '\n'; printf UNCHANGED_REFERENCE=$UNCHANGED_REFERENCE'\n'; printf SERVICE_ADDRESS=$SERVICE_ADDRESS'\n';printf ESCAPED_REFERENCE=$ESCAPED_REFERENCE'\n'; sleep 30; done;
       command:
         - sh
         - -c