diff --git a/bin/simple-apt-update b/bin/simple-apt-update
index 2e654b4..831ee90 100755
--- a/bin/simple-apt-update
+++ b/bin/simple-apt-update
@@ -1,16 +1,34 @@
 #!/usr/bin/env python3
+# simple-apt-update - A GUI for basic tasks of package management using apt
+# Copyright (C) 2023  Tilman Kranz <t.kranz@tk-sls.de>
+#
+# 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 3 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, see <https://www.gnu.org/licenses/>.
+
+##
+# Imports
 
-import re
-import queue
-import threading
 import gi
 import html
 import logging
 import os
+import queue
+import re
 import selectors
 import signal
 import subprocess
 import sys
+import threading
 
 gi.require_version('Gdk', '3.0')
 gi.require_version('Gtk', '3.0')
@@ -21,12 +39,6 @@ except ImportError:
     logging.error("Could not import Gio")
     sys.exit(1)
 
-# try:
-#     from gi.repository import GObject
-# except ImportError:
-#     logging.error("Could not import GObject")
-#     sys.exit(1)
-
 try:
     from gi.repository import GLib
 except ImportError:
@@ -40,6 +52,9 @@ except ImportError:
     sys.exit(1)
 
 
+##
+# Classes
+
 class UpdateWindow(Gtk.ApplicationWindow):
     def clear(self):
         self.buffer.set_text("")
@@ -100,6 +115,11 @@ class UpdateWindow(Gtk.ApplicationWindow):
                 empty_msg=None, env={}):
         self.lock()
         self.clear()
+        self.output_msg = output_msg
+        self.empty_msg = empty_msg
+        self.ignore_stderr = ignore_stderr
+        self.stdout = ''
+        self.stderr = ''
         self.prepend_mesg(
             "INFO",
             "Running command \"%s\" ..." % " ".join(args))
@@ -181,14 +201,23 @@ class UpdateWindow(Gtk.ApplicationWindow):
     def update_buffer(self):
         try:
             text = self.stdout_queue.get(block=False)
+
+            self.stdout += text
             self.append_mesg("STDOUT", text)
+
             match = re.fullmatch(r'EXIT (\d+)', text)
+
             if match is not None:
                 exit_code = int(match.group(1))
+
                 if exit_code != 0:
                     self.append_mesg(
                         "ERROR",
                         "Command exited with code %d" % exit_code)
+                elif self.stdout == '' and self.empty_msg is not None:
+                    self.append_mesg("INFO", self.empty_msg)
+                elif self.stdout != '' and self.output_msg is not None:
+                    self.append_mesg("INFO", self.empty_msg)
 
                 self.unlock()
 
@@ -197,7 +226,11 @@ class UpdateWindow(Gtk.ApplicationWindow):
 
         try:
             text = self.stderr_queue.get(block=False)
-            self.append_mesg("STDERR", text)
+
+            self.stderr += text
+
+            if not self.ignore_stderr:
+                self.append_mesg("STDERR", text)
         except queue.Empty:
             pass
 
@@ -306,6 +339,9 @@ class SimpleAptUpdate(Gtk.Application):
         self.window.show_all()
 
 
+##
+# Main Program
+
 def main():
     application = SimpleAptUpdate()
     exit_status = application.run()