diff --git a/etc/python/common.py b/etc/python/common.py
new file mode 100644
index 0000000..1eb271e
--- /dev/null
+++ b/etc/python/common.py
@@ -0,0 +1,71 @@
+# -*- mode: utf-8 -*-
+#
+# common.py
+# ---------
+#
+# Copyright (C) 2007 Jeremie Dimino <jeremie@dimino.org>
+#
+# This file 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 file 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 Street #330, Boston, MA 02111-1307, USA.
+
+'''Fichier inclu par tous les scripts du plugin Python de bcfg2'''
+
+import sys
+sys.path.append('/usr/scripts/gestion')
+
+def comment(line):
+    '''Écrit un commentaire'''
+    out("# " + line + "\n")
+
+def header(desc, mode="conf-unix"):
+    '''Écrit une en-tête de fichier avec un commentaire'''
+    comment("-*- mode: %s; coding: utf-8 -*-" % mode)
+    @#
+    @# Fichier gere par BCfg2
+    @#
+    lines = desc.split('\n')
+    if lines[-1] == "":
+        lines.pop()
+    for line in lines:
+        comment(line)
+    out("\n")
+
+def var(name, value, doc=None):
+    '''Écrit la définition d'une variable'''
+    if doc: comment(doc)
+    out("%s = %s\n" % (name, value))
+
+# Le nom d'hote court, la partie avant le premier '.'
+hostname = metadata.hostname.split('.',1)[0]
+
+# Le nom d'hote sur le vlan public
+pubhostname = hostname + ".crans.org"
+
+# Le nom d'hote sur le vlan
+admhostname = hostname + ".adm.crans.org"
+
+def has(group):
+    return group in metadata.groups
+
+def yesno(b):
+    if b:
+        return "yes"
+    else:
+        return "no"
+
+def onoff(b):
+    if b:
+        return "on"
+    else:
+        return "off"