Index: Doc/using/cmdline.rst
===================================================================
--- Doc/using/cmdline.rst	(revision 76237)
+++ Doc/using/cmdline.rst	(working copy)
@@ -353,6 +353,8 @@
       :mod:`warnings` -- the warnings module
 
       :pep:`230` -- Warning framework
+      
+      :envvar:`PYTHONWARNINGS`
 
 
 .. cmdoption:: -x
@@ -526,8 +528,13 @@
    If this environment variable is set, ``sys.argv[0]`` will be set to its
    value instead of the value got through the C runtime.  Only works on
    Mac OS X.
+   
+.. envvar:: PYTHONWARNINGS
 
+   This is the equivalent to the :option:`-W` option. If set to a comma
+   separated string, it is equivalent to specifying :option:`-W` multiple times.
 
+
 Debug-mode variables
 ~~~~~~~~~~~~~~~~~~~~
 
Index: Modules/main.c
===================================================================
--- Modules/main.c	(revision 76237)
+++ Modules/main.c	(working copy)
@@ -83,6 +83,7 @@
          can be supplied multiple times to increase verbosity\n\
 -V     : print the Python version number and exit (also --version)\n\
 -W arg : warning control; arg is action:message:category:module:lineno\n\
+         also PYTHONWARNING=arg\n\
 -x     : skip first line of source, allowing use of non-Unix forms of #!cmd\n\
 ";
 static char *usage_4 = "\
@@ -420,6 +421,16 @@
 	    (p = Py_GETENV("PYTHONNOUSERSITE")) && *p != '\0')
 		Py_NoUserSiteDirectory = 1;
 
+    if ((p = Py_GETENV("PYTHONWARNINGS")) && *p != '\0')
+    {
+        char* warning = strtok(p, ",");
+        while (warning != NULL)
+        {
+            PySys_AddWarnOption(warning);
+            warning = strtok(NULL, ",");
+        }
+    }
+
 	if (command == NULL && module == NULL && _PyOS_optind < argc &&
 	    strcmp(argv[_PyOS_optind], "-") != 0)
 	{