diff --git a/CoTeTo/CLI.py b/CoTeTo/CLI.py
index a45817b..738085d 100644
--- a/CoTeTo/CLI.py
+++ b/CoTeTo/CLI.py
@@ -82,24 +82,18 @@ def main():
 
     elif args.data_source:
         # execute the generator
-        o = g.execute(args.data_source)
-        if len(o) == 1:
-            # single file output
-            ext = list(o.keys())[0]
-            if args.output:
-                outFile = open(args.output[0] + ext, 'w')
-                outFile.write(o[ext].read())
-                outFile.close()
-            else:
-                sys.stdout.write(o[ext].read())
+        if args.output:
+            # output to files: let the generator handle file saving
+            g.execute(args.data_source, args.output[0])
         else:
-            # multi file output
-            if args.output:
-                for ext in o:
-                    outFile = open(args.output[0] + ext, 'w')
-                    outFile.write(o[ext].read())
-                    outFile.close()
+            # print to stdout
+            o = g.execute(args.data_source)
+            if len(o) == 1:
+                # single file output
+                ext = list(o.keys())[0]
+                sys.stdout.write(o[ext].read())
             else:
+                # files separated by a line
                 for ext in o:
                     sys.stdout.write('### FILE: %s\n' % ext)
                     sys.stdout.write(o[ext].read())
diff --git a/CoTeTo/GUI.py b/CoTeTo/GUI.py
index 99fd615..b124315 100644
--- a/CoTeTo/GUI.py
+++ b/CoTeTo/GUI.py
@@ -266,15 +266,11 @@ def executeGenerator(self):
             self.outputInput.setText(outputBase)
         if not os.path.isabs(outputBase):
             outputBase = os.path.abspath(outputBase)
-        x = self.activeGenerator.execute(uriList)
-        for ext in x:
-            outputFile = outputBase + ext
-            o = open(outputFile, 'w')
-            o.write(x[ext].read())
-            o.close()
-            if self.openOutputButton.isChecked():
-                QtGui.QDesktopServices.openUrl(QtCore.QUrl.fromLocalFile(outputFile))
-
+        x = self.activeGenerator.execute(uriList, outputBase)
+        if self.openOutputButton.isChecked():
+           for ext in x:
+               QtGui.QDesktopServices.openUrl(QtCore.QUrl.fromLocalFile(x[ext]))
+ 
     def closeEvent(self, e):
         # first reset output streams to standard settings
         XStream.reset()
diff --git a/CoTeTo/Generator.py b/CoTeTo/Generator.py
index 303df3c..fa9ba2a 100644
--- a/CoTeTo/Generator.py
+++ b/CoTeTo/Generator.py
@@ -186,19 +186,41 @@ def executeFilter(self):
         function = getattr(module, functionName)
         function(self.data, self.controller.systemCfg, self.cfg, self.logger)
 
-    def executeTemplates(self):
-        """execeute all templates, return the output buffers and extensions"""
+    def executeTemplates(self, outputBasename=None):
+        """execeute all templates, return the output buffers and extensions -
+        if outputBasename is given, save file and return file names instead of the buffers"""
         tmpls = sorted([s for s in self.cfg.sections() if s.upper().startswith('TEMPLATE')])
-        txt = {}
+        res = {}
         for tmpl in tmpls:
             ext = self.cfg[tmpl].get('ext', '')
-            if ext in txt:
-                while ext in txt:
+            if ext in res:
+                while ext in res:
                     ext.append('X')
                 self.logger.error('GEN | file extension already exists, using %s!' % ext)
             self.logger.debug('GEN | processing template setup ' + tmpl)
-            txt[ext] = self.executeTemplate(tmpl)
-        return txt
+            buf = self.executeTemplate(tmpl)
+            if outputBasename is None:
+                # return buffer
+                res[ext] = buf
+                if self.cfg[tmpl].get('postExec', ''):
+                    self.logger.error('GEN | postExec defined but saving to buffer instead of file: skipping postExec in ' + tmpl)
+            else:
+                # save file and return file name
+                fname = outputBasename + ext
+                o = open(fname, 'w')
+                o.write(buf.read())
+                o.close()
+                # buf.close() ?
+                res[ext] = fname
+                # post execution cmd?
+                cmd = self.cfg[tmpl].get('postExec', '')
+                if cmd:
+                    self.logger.debug('GEN | starting postExec command: %s: ', cmd)
+                    try:
+                        exec(cmd, globals(), locals())
+                    except BaseException:
+                        self.logger.exception('GEN | error during postExec: %s: ', cmd)
+        return res
 
     def executeTemplate(self, name):
         """execeute a single template with the data, return the output buffer"""
@@ -230,7 +252,7 @@ def executeTemplate(self, name):
         else:
             raise Exception('Unknown template system: ' + tmplType)
 
-    def execute(self, uriList=[]):
+    def execute(self, uriList=[], outputBasename = None):
         if not self.loader:
             raise Exception('Generator is not valid - canceling execution!')
         # fill data model from the loader using the data URIs
@@ -238,8 +260,9 @@ def execute(self, uriList=[]):
         # apply filter
         if self.cfg.has_section('FILTER'):
             self.executeFilter()
-        # handle data to template, return text buffer
-        return self.executeTemplates()
+        # handle data to templates, return text buffers or file names
+        return self.executeTemplates(outputBasename)
+
 
     # make the generator executable
     __call__ = execute
diff --git a/Generators/TestPostExec/Filters/Filter01.py b/Generators/TestPostExec/Filters/Filter01.py
new file mode 100644
index 0000000..d426454
--- /dev/null
+++ b/Generators/TestPostExec/Filters/Filter01.py
@@ -0,0 +1,21 @@
+# a filter function is called with the following arguments:
+#   d - the data dictionary read from the loader
+#   systemCfg - system configuration
+#   generatorCfg - generator configuration
+#   logger - a logger instance
+
+
+def filter01(d, systemCfg, generatorCfg, logger):
+
+    # spread a message
+    logger.debug('hi there! This is a filter running from module: ' + __file__)
+
+    x = d['dummy']
+
+    # manipulate some data
+    x['foo'] += 1
+
+    # add more data
+    x['bar'] = 2.0 * x['foo']
+
+    # no return needed - data is manipulated inplace
diff --git a/Generators/TestPostExec/Package.inf b/Generators/TestPostExec/Package.inf
new file mode 100644
index 0000000..f39e17f
--- /dev/null
+++ b/Generators/TestPostExec/Package.inf
@@ -0,0 +1,22 @@
+[GENERATOR]
+name = TestPostExec
+version = 0.1
+description = test the post execution feature
+author = Joerg Raedler jraedler@udk-berlin.de
+
+[LOADER]
+name = TestDummy
+minVer = 0.1
+maxVer = 2.0
+
+[FILTER]
+module = Filter01
+function = filter01
+
+[TEMPLATE]
+topFile = Main.mako
+type = mako
+# be VERY carefull with the postexec feature, it has complete access
+# to the whole namespace and will run this code without checking!
+# You can use "fname" to access the name of the generated file
+postExec = os.system("dir "+fname)
diff --git a/Generators/TestPostExec/Templates/Main.mako b/Generators/TestPostExec/Templates/Main.mako
new file mode 100644
index 0000000..fed1400
--- /dev/null
+++ b/Generators/TestPostExec/Templates/Main.mako
@@ -0,0 +1,14 @@
+#
+#   CoTeTo
+#       Version:  ${systemCfg['version']}
+#       Platform: ${systemCfg['platform']}
+#       Path:     ${systemCfg['path']}
+#       Gen-Path: ${', '.join(systemCfg['generatorPath'])}
+#
+#   Generator
+#       Name:     ${generatorCfg['GENERATOR'].get('name')}
+#       Version:  ${generatorCfg['GENERATOR'].get('version')}
+
+The value of foo is ${d['dummy']['foo']}.
+
+<%include file="Sub.mako"/>
diff --git a/Generators/TestPostExec/Templates/Sub.mako b/Generators/TestPostExec/Templates/Sub.mako
new file mode 100644
index 0000000..c082879
--- /dev/null
+++ b/Generators/TestPostExec/Templates/Sub.mako
@@ -0,0 +1,2 @@
+Hello, I'm a sub template!
+bar = ${d['dummy']['bar']}