- remove default=None with argparse is redundant since it's the

default value already.
- use the argparse.ArgumentDefaultsHelpFormatter as the
  formatter_class, to print out automatically the default values

pelican/__init__.py

@@ -135,7 +135,8 @@ class Pelican(object):
 
 def main():
     parser = argparse.ArgumentParser(description="""A tool to generate a
-    static blog, with restructured text input files.""")
+    static blog, with restructured text input files.""",
+        formatter_class=argparse.ArgumentDefaultsHelpFormatter)
 
     parser.add_argument(dest='path', nargs='?',
         help='Path where to find the content files.')
@@ -145,11 +146,11 @@ def main():
     parser.add_argument('-o', '--output', dest='output',
         help='Where to output the generated files. If not specified, a '
              'directory will be created, named "output" in the current path.')
-    parser.add_argument('-m', '--markup', default=None, dest='markup',
+    parser.add_argument('-m', '--markup', dest='markup',
         help='The list of markup language to use (rst or md). Please indicate '
              'them separated by commas.')
-    parser.add_argument('-s', '--settings', dest='settings', default='',
-        help='The settings of the application. Default to False.')
+    parser.add_argument('-s', '--settings', dest='settings',
+        help='The settings of the application.')
     parser.add_argument('-d', '--delete-output-directory',
                         dest='delete_outputdir',
         action='store_true', help='Delete the output directory.')