diff --git a/libexec/rbenv-version-file-write b/libexec/rbenv-version-file-write
index b42764b3..0435cf14 100755
--- a/libexec/rbenv-version-file-write
+++ b/libexec/rbenv-version-file-write
@@ -5,7 +5,8 @@ RBENV_VERSION_FILE="$1"
 RBENV_VERSION="$2"
 
 if [ -z "$RBENV_VERSION" ] || [ -z "$RBENV_VERSION_FILE" ]; then
-  echo "usage: rbenv write-version-file filename version" >&2
+  echo "usage: rbenv write-version-file FILENAME VERSION" >&2
+  exit 1
 fi
 
 # Make sure the specified version is installed.