Fix upgrade command

Signed-off-by: Weiyang Zhu <cnresonant@gmail.com>
2016-02-01 12:59:21 +08:00 · 2016-02-01 12:59:21 +08:00 · a80c404cc6
--- a/docs/installation/linux/ubuntulinux.md
+++ b/docs/installation/linux/ubuntulinux.md
@ -421,7 +421,7 @@ to start the docker daemon on boot
 To install the latest version of Docker with `apt-get`:
-    $ apt-get upgrade docker-engine
+    $ sudo apt-get upgrade docker-engine
 ## Uninstallation