diff --git a/scripts/MakeSingleHeader.py b/scripts/MakeSingleHeader.py
index bb83e8cd..8dd6d99a 100755
--- a/scripts/MakeSingleHeader.py
+++ b/scripts/MakeSingleHeader.py
@@ -54,6 +54,8 @@ class HeaderFile(object):
 
         self.body = '\n// From {}:\n\n'.format(inc) + inner[inner.find('namespace'):]
 
+        self.namespace = None
+
     def __add__(self, other):
         out = copy(self)
         out.headers |= other.headers
@@ -69,8 +71,16 @@ class HeaderFile(object):
     def verbatim_str(self):
         return '\n'.join(self.verbatim)
 
+    def insert_namespace(self, namespace):
+        self.namespace = namespace
+
+    def macro_replacement(self, before, after):
+        self.verbatim = [x.replace(before, after) for x in self.verbatim]
+        self.body = self.body.replace(before, after)
+
+
     def __str__(self):
-        return '''\
+        result = '''\
 #pragma once
 
 // CLI11: Version {self.VERSION}
@@ -87,12 +97,18 @@ class HeaderFile(object):
 // Standard combined includes:
 
 {self.header_str}
-{self.verbatim_str}
-{self.body}
 '''.format(self=self)
 
+        if self.namespace:
+             result += '\nnamespace ' + self.namespace + ' {\n\n'
+        result += '{self.verbatim_str}\n{self.body}\n'.format(self=self)
+        if self.namespace:
+            result += '} // namespace ' + self.namespace + '\n\n'
 
-def MakeHeader(output, main_header, include_dir = '../include'):
+        return result
+
+
+def MakeHeader(output, main_header, include_dir = '../include', namespace=None, macro=None):
     # Set tag if possible to class variable
     try:
         HeaderFile.TAG = check_output(['git', 'describe', '--tags', '--always'], cwd=str(DIR)).decode("utf-8").strip()
@@ -114,18 +130,29 @@ def MakeHeader(output, main_header, include_dir = '../include'):
     headers = [HeaderFile(base_dir, inc) for inc in include_files]
     single_header = reduce(operator.add, headers)
 
+    if macro:
+        before, after = macro
+        print("Converting macros", before, "->", after)
+        single_header.macro_replacement(before, after)
+
+    if namespace:
+        print("Adding namespace", namespace)
+        single_header.insert_namespace(namespace)
+
     with open(output, 'w') as f:
         f.write(str(single_header))
 
     print("Created", output)
 
-
 if __name__ == '__main__':
-    parser = argparse.ArgumentParser()
+    parser = argparse.ArgumentParser(usage='Convert source to single header include. Can optionally add namespace and search-replace replacements (for macros).')
     parser.add_argument("output", help="Single header file output")
     parser.add_argument("--main", default='CLI/CLI.hpp', help="The main include file that defines the other files")
-    parser.add_argument("--include", default='../include')
+    parser.add_argument("--include", default='../include', help="The include directory")
+    parser.add_argument("--namespace", help="Add an optional namespace")
+    parser.add_argument("--macro", nargs=2, help="Macro replacement: CLI11_ NEW_PREFIX_")
     args = parser.parse_args()
 
-    MakeHeader(args.output, args.main, args.include)
+
+    MakeHeader(args.output, args.main, args.include, args.namespace, args.macro)