diff --git a/packages/docker/linux b/packages/docker/linux
index 0356a93..a4604ad 100755
--- a/packages/docker/linux
+++ b/packages/docker/linux
@@ -1 +1,2 @@
-wget -O- https://get.docker.com | bash
+#!/bin/sh
+which docker || wget -O- https://get.docker.com | bash