diff --git a/README.md b/README.md
index 8c9de75..da5e9cf 100644
--- a/README.md
+++ b/README.md
@@ -36,7 +36,7 @@ USAGE
 Commandline usage: (if installed via pypi)
 ```
 usage: chevron [-h] [-v] [-d DATA] [-p PARTIALS_PATH] [-e PARTIALS_EXT]
-               [-l DEF_LDEL] [-r DEF_RDEL]
+               [-l DEF_LDEL] [-r DEF_RDEL] [-w] [-k]
                template
 
 positional arguments:
@@ -55,6 +55,9 @@ optional arguments:
                         The default left delimiter, "{{" by default.
   -r DEF_RDEL, --right-delimiter DEF_RDEL
                         The default right delimiter, "}}" by default.
+  -w, --warn            Print a warning to stderr for each undefined template
+                        key encountered
+  -k, --keep            Keep undefined template keys unchanged
 ```
 
 Python usage with strings
diff --git a/chevron/main.py b/chevron/main.py
index 02ba09a..391488a 100755
--- a/chevron/main.py
+++ b/chevron/main.py
@@ -93,6 +93,10 @@ def is_dir(arg):
                         help='Print a warning to stderr for each undefined template key encountered',
                         action='store_true')
 
+    parser.add_argument('-k', '--keep', dest='keep',
+                        help='Keep undefined template keys unchanged',
+                        action='store_true')
+
 
     args = vars(parser.parse_args())
 
diff --git a/chevron/metadata.py b/chevron/metadata.py
index 19912aa..d17afd8 100644
--- a/chevron/metadata.py
+++ b/chevron/metadata.py
@@ -1 +1 @@
-version = '0.13.1'
+version = '0.13.2'