diff --git a/doc/src/brew-cask.1.md b/doc/src/brew-cask.1.md
index 8b07679c94..c82baeb44e 100644
--- a/doc/src/brew-cask.1.md
+++ b/doc/src/brew-cask.1.md
@@ -79,8 +79,9 @@ names, and other aspects of this manual are still subject to change.
     <Cask> is usually the name of a Cask as returned by `brew cask search`,
     but see [OTHER WAYS TO SPECIFY A CASK][] for variations.
 
-  * `list` or `ls` [<Casks>]:
-    Without any arguments, list all installed Casks.
+  * `list` or `ls` [-1] [<Casks>]:
+    Without any arguments, list all installed Casks.  With `-1`, always
+    format the output in a single column.
 
     If <Casks> are given, list the installed files for <Casks>.