diff --git a/tools/build-addon-index.py b/tools/build-addon-index.py
index d2bb7aacc31..8d574634e34 100755
--- a/tools/build-addon-index.py
+++ b/tools/build-addon-index.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 #
 # SuperTux
 # Copyright (C) 2014 Ingo Ruhnke <grumbel@gmail.com>
@@ -31,7 +31,8 @@ def escape_str(string):
     return "\"%s\"" % string.replace("\"", "\\\"")
 
 
-class Addon(object):
+class Addon:
+
     def __init__(self, filename):
         lst = sexpr.parse(filename)
         if lst[0][0] != "supertux-addoninfo":
@@ -95,7 +96,7 @@ def generate_index(fout, directory, base_url, zipdir):
     for addon_dir in os.listdir(directory):
         addon_dir = os.path.join(directory, addon_dir)
         if os.path.isdir(addon_dir):
-            print addon_dir
+            # print(addon_dir)
             nfos = glob.glob(os.path.join(addon_dir, "*.nfo"))
             if len(nfos) == 0:
                 raise Exception(".nfo file missing from %s" % addon_dir)
@@ -104,13 +105,20 @@ def generate_index(fout, directory, base_url, zipdir):
             else:
                 try:
                     process_addon(fout, addon_dir, nfos[0], base_url, zipdir)
-                except Exception, e:
+                except Exception as e:
                     sys.stderr.write("%s: ignoring addon because: %s\n" % (addon_dir, e))
     fout.write(")\n\n;; EOF ;;\n")
 
 
+EXAMPLE_TEXT="""Example:
+
+    ./build-addon-index.py -z ../../addons/repository/ ../../addons/src/"""
+
+
 if __name__ == "__main__":
-    parser = argparse.ArgumentParser(description='Addon Index/Zip Generator')
+    parser = argparse.ArgumentParser(description="Addon Index/Zip Generator",
+                                     epilog=EXAMPLE_TEXT,
+                                     formatter_class=argparse.RawDescriptionHelpFormatter)
     parser.add_argument('DIRECTORY',  type=str, nargs=1,
                         help="directory containing the mods")
     parser.add_argument('-o', '--output', metavar='FILE', type=str, required=False,
@@ -129,4 +137,5 @@ def generate_index(fout, directory, base_url, zipdir):
         with open(args.output, "w") as fout:
             generate_index(fout, args.DIRECTORY[0], args.url, args.zipdir)
 
+
 # EOF #
diff --git a/tools/sexpr.py b/tools/sexpr.py
index 98d2e7b09ae..cc1669396c2 100755
--- a/tools/sexpr.py
+++ b/tools/sexpr.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 # Copyright (c) 2014 Ingo Ruhnke <grumbel@gmail.com>
 #
@@ -97,15 +97,15 @@ def parse(text):
         raise Exception("error: list not closed")
 
 if __name__ == "__main__":
-    print "parsing..."
+    print("parsing...")
     result = parse(r'(() ("bar" foo) ()) () bar ')
-    print "1.", result
-    print "2.", parse(""";;comment
-    ("Hello World" 5 1 123) ("Hello" 123 123 "foobar") ;; comment""")
-    print "3.", parse(r'(8(8)8)')
-    print "4.", parse(r'')
-    print "5.", parse(r'  ')
+    print("1.", result)
+    print("2.", parse(""";;comment
+    ("Hello World" 5 1 123) ("Hello" 123 123 "foobar") ;; comment"""))
+    print("3.", parse(r'(8(8)8)'))
+    print("4.", parse(r''))
+    print("5.", parse(r'  '))
     with codecs.open("white.stf", encoding='utf-8') as fin:
-        print "6.", parse(fin.read())
+        print("6.", parse(fin.read()))
 
 # EOF #