--- a/sphinxarg/parser.py
+++ b/sphinxarg/parser.py
@@ -10,7 +10,7 @@ def parser_navigate(parser_result, path,
     if isinstance(path, str):
         if path == '':
             return parser_result
-        path = re.split('\s+', path)
+        path = re.split(r'\s+', path)
     current_path = current_path or []
     if len(path) == 0:
         return parser_result
@@ -35,7 +35,7 @@ def _try_add_parser_attribute(data, pars
     if not isinstance(attribval, str):
         return
     if len(attribval) > 0:
-        data[attribname] = attribval
+        data[attribname] = attribval % {'prog': data['prog']}
 
 
 def _format_usage_without_prefix(parser):
--- a/test/test_parser.py
+++ b/test/test_parser.py
@@ -129,7 +129,7 @@ def test_parse_description():
 
 
 def test_parse_nested():
-    parser = argparse.ArgumentParser()
+    parser = argparse.ArgumentParser(prog='test_parse_nested')
     parser.add_argument('foo', default=False, help='foo help')
     parser.add_argument('bar', default=False)
 
@@ -157,8 +157,8 @@ def test_parse_nested():
         {
             'name': 'install',
             'help': 'install help',
-            'usage': 'usage: py.test install [-h] [--upgrade] ref',
-            'bare_usage': 'py.test install [-h] [--upgrade] ref',
+            'usage': 'usage: test_parse_nested install [-h] [--upgrade] ref',
+            'bare_usage': 'test_parse_nested install [-h] [--upgrade] ref',
             'action_groups': [
                 {
                     'title': 'Positional Arguments',
@@ -188,7 +188,7 @@ def test_parse_nested():
 
 
 def test_parse_nested_traversal():
-    parser = argparse.ArgumentParser()
+    parser = argparse.ArgumentParser(prog='test_parse_nested_traversal')
 
     subparsers1 = parser.add_subparsers()
     subparser1 = subparsers1.add_parser('level1')
@@ -223,8 +223,8 @@ def test_parse_nested_traversal():
         {
             'name': 'level3',
             'help': '',
-            'usage': 'usage: py.test level1 level2 level3 [-h] foo bar',
-            'bare_usage': 'py.test level1 level2 level3 [-h] foo bar',
+            'usage': 'usage: test_parse_nested_traversal level1 level2 level3 [-h] foo bar',
+            'bare_usage': 'test_parse_nested_traversal level1 level2 level3 [-h] foo bar',
             'action_groups': [
                 {
                     'title': 'Positional Arguments',
@@ -265,6 +265,20 @@ def test_fill_in_default_prog():
     ]
 
 
+def test_fill_in_description_epilog():
+    """
+    Ensure that %(prog)s gets filled in inside description and epilog.
+    """
+    parser = argparse.ArgumentParser(
+        prog='test_fill_in_description',
+        description='Welcome to %(prog)s',
+        epilog='%(prog)s salutes you')
+    data = parse_parser(parser)
+
+    assert data['description'] == 'Welcome to test_fill_in_description'
+    assert data['epilog'] == 'test_fill_in_description salutes you'
+
+
 def test_string_quoting():
     """
     If an optional argument has a string type and a default, then the default should be in quotes.