diff --git a/README.md b/README.md
index 32fa888..dde437c 100644
--- a/README.md
+++ b/README.md
@@ -37,3 +37,4 @@ they are added as-needed.
   number, inclusive. If two arguments, chooses a random integer between the two numbers, inclusive.
 * `choose [X [Y [Z ...]]]` - chooses a random item from the supplied list of items.
 * `round X [Y]` - rounds a number X to an optional Y digits.
+* `cat [X [Y [Z ...]]]` - concatenates all arguments together, without spaces.