Closes kentcdodds#153 with documentation update

README.md

@@ -82,10 +82,12 @@ The `NODE_ENV` environment variable will be set by `cross-env`
 You can also split a command into several ones, or separate the environment
 variables declaration from the actual command execution. You can do it this way:
 
-```json
+```javascript
 {
   "scripts": {
     "parentScript": "cross-env GREET=\"Joe\" npm run childScript",
+
+    // Prints "Hello Joe" on POSIX systems (e.g. OS X, Linux, etc)
     "childScript": "echo Hello $GREET"
   }
 }
@@ -97,6 +99,33 @@ the parent. This is quite useful for launching the same command with different
 env variables or when the environment variables are too long to have everything
 in one line.
 
+On Windows you will still need to wrap environment variables passed to child
+scripts in `%` characters:
+
+```javascript
+{
+  "scripts": {
+    "parentScript": "cross-env GREET=\"Joe\" npm run childScript",
+
+    // Prints "Hello Joe" on Windows
+    "childScript": "echo Hello %GREET%"
+  }
+}
+```
+
+They will be available to subprocesses as normal however:
+
+```javascript
+{
+  "scripts": {
+    "parentScript": "cross-env GREET=\"Joe\" npm run childScript",
+
+    // Prints "Hello Joe" on Windows and POSIX systems
+    "childScript": "node -e \"console.log('Hello', process.env.GREET)\""
+  }
+}
+```
+
 If you preceed a dollar sign with an odd number of backslashes the expression statement will not be replaced. Note that this means backslashes after the JSON string escaping took place. `"FOO=\\$BAR"` will not be replaced. `"FOO=\\\\$BAR"` will be replaced though.
 
 Lastly, if you want to pass a JSON string (e.g., when using [ts-loader]), you can do as follows: