Update ubuntu-installation.md

docs/ubuntu-installation.md

@@ -29,10 +29,10 @@ Don't install updates if Ubuntu asks to. The scripts will.
 
 You can overwrite the files of the folder `system` by setting an environment variable named `OVERWRITE` with the format : `Destination folder;Git URL`.
 
-For example to write the content of the repository [github.com/xpetit/.ssh](github.com/xpetit/.ssh) in the system folder `/root/.ssh` :
+For example to write the content of the repository [github.com/xpetit/custom](github.com/xpetit/custom) in the system folder :
 
 ```shell
-export 'OVERWRITE=root/.ssh;https://github.com/xpetit/.ssh.git'
+export 'OVERWRITE=.;https://github.com/xpetit/custom.git'
 ```
 
 ## OS configuration