Fix docker format build example
@@ -13,7 +13,7 @@ then start the `onboot` and `service` containers. The example below shows how yo
can run `nginx` on either of these base configs.
```
-moby build -format docker -o - docker.yml nginx.yml | docker build -t dockertest -
+moby build -format docker -o - linuxkit.yml nginx.yml | docker build -t dockertest -
docker run -d -p 80:80 --privileged dockertest
moby build -format kernel+initrd linuxkit.yml nginx.yml
