diff --git a/src/rougail/user-data-environment/config.py b/src/rougail/user-data-environment/config.py
index aedf23e..e4344c6 100644
--- a/src/rougail/user-data-environment/config.py
+++ b/src/rougail/user-data-environment/config.py
@@ -20,6 +20,11 @@ You should have received a copy of the GNU General Public License
 along with this program; if not, write to the Free Software
 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 """
+
+"rougail environment variable prefix"
+rougail_environment_var = "ROUGAIL_"
+
+
 def get_rougail_config(*,
                        backward_compatibility=True,
                        ) -> dict:
diff --git a/src/rougail/user-data-environment/data.py b/src/rougail/user-data-environment/data.py
index c0b7c78..abb8136 100644
--- a/src/rougail/user-data-environment/data.py
+++ b/src/rougail/user-data-environment/data.py
@@ -87,8 +87,22 @@ class RougailUserDataEnvironment:
         ismulti = option.ismulti()
         type_obj = None
         type_obj = CONVERT_OPTION.get(option_type, {}).get("func")
-        print(dir(option))
-        option.value.set(["78", "52"])
+
+        from .helper import get_rougail_environment_var, get_rougail_environment_dict
+        rougail_environment_var = get_rougail_environment_var()
+        option_name = option.path()
+        if option_name in rougail_environment_var:
+            option.value.set(get_rougail_environment_dict()[option_name])        
+        #option.value.set(["78", "52"])
+        # TODO 
+        # - tester les var commençant par ROUGAIL_
+        # 'ROUGAIL_'
+        # tester si c'est une multi
+        # le CONVERT_TYPE ne marchera pas si c'est une multi
+        # récupérer le nam de l'option pour voir si elle est dans l'env
+        
+        
+        
         #RougailValidator.option = option
         #RougailValidator.option_type = {'type': option_type,
         #                                'func': type_obj,
diff --git a/src/rougail/user-data-environment/helper.py b/src/rougail/user-data-environment/helper.py
new file mode 100644
index 0000000..e09d1ae
--- /dev/null
+++ b/src/rougail/user-data-environment/helper.py
@@ -0,0 +1,38 @@
+"""
+Helper file for Rougail-user-data-environment
+
+Silique (https://www.silique.fr)
+Copyright (C) 2024
+
+distribued with GPL-2 or later license
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+"""
+
+import os
+
+from .config import rougail_environment_var
+
+def get_rougail_environment_var():
+    "lists all rougail environment variables (that is, wich startswith ROUGAIL_)"
+    all_envvar = os.environ
+    return [envvar.replace(rougail_environment_var, '') for envvar in all_envvar if envvar.startswith(rougail_environment_var)]
+
+def get_rougail_environment_dict():
+    "rougail environment variables as a key/value dict"
+    rougail_environment_dict = dict()
+    for var in get_rougail_environment_var():
+        rougail_environment_dict[var] = os.environ[rougail_environment_var + var]
+    return rougail_environment_dict