diff --git a/Doc/using/cmdline.rst b/Doc/using/cmdline.rst
index 4b2793f..2537c48 100644
--- a/Doc/using/cmdline.rst
+++ b/Doc/using/cmdline.rst
@@ -541,7 +541,8 @@
 .. envvar:: PYTHONDONTWRITEBYTECODE
 
    If this is set, Python won't try to write ``.pyc`` or ``.pyo`` files on the
-   import of source modules.
+   import of source modules.  This is equivalent to specifying the :option:`-B`
+   option.
 
    .. versionadded:: 2.6