diff --git a/Scripting:-set-&-variables.md b/Scripting:-set-&-variables.md
index a277142..68c3f36 100644
--- a/Scripting:-set-&-variables.md
+++ b/Scripting:-set-&-variables.md
@@ -7,5 +7,14 @@
 ### User Defined Variables
 
 ### Environmental Variables
+These are variables with values that cannot redefined. 
+
+**Example:**  
+`echo $[GM9OUT]`  
+**Output:** 0:/gm9/out
+
+`set GM9OUT "0:/gm9/in"`  
+`echo $[GM9OUT]`  
+**Output:** 0:/gm9/out
 
 ## Notes
\ No newline at end of file