containers.md

@@ -5,7 +5,7 @@ On atlas we provide these container software:
 - docker
 - singularity (recommended)
 
-To use docker, you have to ask an account to system administrators, but we recommend to use singularity if possible.
+To use docker, you have to ask an account to system administrators, but we recommend to use singularity whenever it is possible.
 
 # Preriquisites
 
@@ -39,9 +39,16 @@ Now, if you want to go inside the container in a shell environment, just type
 ```sh
 singularity shell vsoch-singularity-hello-world-master.img
 ```
-and now you are inside the image isolated from the host system!
+and now you are inside the image isolated from the host system! By default, the home directory is mounted inside the image.
+To edit an image, add the option `-w`
+```sh
+singularity shell -w vsoch-singularity-hello-world-master.img
+```
+Note that you always have the same privilege in the image than on the host (you can't edit directory you do not have rights!).
+
+If you want to modify the image anyway, you have to download the image on a machine where you are the administrator and edit the image as root.
 
-Remember that you always have the same priviledge than on the host, you can't edit root directory. If you want to edit an image, you have to download it on your own machine, then do the changes.
 
+#### Feel++ users
 
-Note for feel++ users, images are available on [IRMA gitlab](https://gitlab.math.unistra.fr/feelpp/feelpp-singularity-images)
+CI generated images are available on [IRMA gitlab](https://gitlab.math.unistra.fr/feelpp/feelpp-singularity-images)