simplify /etc/hosts management

Documentation/For_ops/INSTALL/INSTALL_DEV_Ubuntu_16.04.md

@@ -353,10 +353,10 @@ done
 
 ## APACHE Vhost preparation
 
-As `root`, edit `/etc/hosts` and add `comptoir-srv.local` next to the "localhost" entry:
+As `root`, do:
 
 ```
-127.0.0.1	localhost my-computer-name comptoir-srv.local 
+cat "127.0.0.1	comptoir-srv.local" >> /etc/hosts
 ```
 
 ## APACHE Vhost creation "comptoir-srv"