diff --git a/pydu/file.py b/pydu/file.py
index d169d97..4c8bf9e 100644
--- a/pydu/file.py
+++ b/pydu/file.py
@@ -4,17 +4,33 @@ import shutil
 
 
 # todo tests and docs
-def makedirs(path, mode=0o755, ignore_errors=False, exist_ok=True):
+def makedirs(path, mode=0o755, ignore_errors=False, exist_ok=False):
+    """
+    Create a leaf directory and all intermediate ones.
+
+    Based on os.makedirs, but also supports ignore_errors which will
+    ignore all errors raised by os.makedirs.
+    """
+    if exist_ok and os.path.exists(path):
+        return
     try:
         os.makedirs(path, mode)
     except Exception:
         if not ignore_errors:
-            if not exist_ok:
-                raise OSError('{} is exist'.format(path))
             raise OSError('Create dir: {} error.')
 
 
 def remove(path, ignore_errors=False, onerror=None):
+    """
+    Remove a file or directory.
+
+    If ignore_errors is set, errors are ignored; otherwise, if onerror
+    is set, it is called to handle the error with arguments (func,
+    path, exc_info) where func is platform and implementation dependent;
+    path is the argument to that function that caused it to fail; and
+    exc_info is a tuple returned by sys.exc_info().  If ignore_errors
+    is False and onerror is None, an exception is raised.
+    """
     if ignore_errors:
         def onerror(*args):
             pass
@@ -32,11 +48,27 @@ def remove(path, ignore_errors=False, onerror=None):
 
 
 def removes(paths, ignore_errors=False, onerror=None):
+    """
+    Remove a list of file and/or directory.
+
+    If ignore_errors is set, errors are ignored; otherwise, if onerror
+    is set, it is called to handle the error with arguments (func,
+    path, exc_info) where func is platform and implementation dependent;
+    path is the argument to that function that caused it to fail; and
+    exc_info is a tuple returned by sys.exc_info().  If ignore_errors
+    is False and onerror is None, an exception is raised.
+    """
     for path in paths:
         remove(path, ignore_errors=ignore_errors, onerror=onerror)
 
 
 def open_file(path, mode='wb+', buffer_size=-1, ignore_errors=False):
+    """
+    Open a file, defualt mode 'wb+'.
+
+    If path not exists, it will be created automatically.
+    If ignore_errors is set, errors are ignored.
+    """
     f = None
     try:
         if path and not os.path.isdir(path):
diff --git a/tests/test_file.py b/tests/test_file.py
index fc64537..6694c31 100644
--- a/tests/test_file.py
+++ b/tests/test_file.py
@@ -4,16 +4,19 @@ import pytest
 
 
 class Testmakedirs():
-    def test_makedirs(self,tmpdir):
+    def test_makedirs(self, tmpdir):
         path = str(tmpdir.join('test'))
         makedirs(path)
         assert os.path.exists(path)
 
-    def test_makedirs_with_exists_path(self,tmpdir):
+    def test_makedirs_with_exists_path(self, tmpdir):
         path = str(tmpdir.join('test'))
         makedirs(path)
-        with pytest.raises(Exception) as e_info:
-            makedirs(path, exist_ok=True)
+
+        makedirs(path, exist_ok=True)
+
+        with pytest.raises(Exception):
+            makedirs(path, exist_ok=False)
 
     def test_makedirs_with_ignore_error(self, tmpdir):
         path = str(tmpdir.join('test'))
@@ -23,8 +26,8 @@ class Testmakedirs():
     def test_makedirs_without_ignore_error(self, tmpdir):
         path = str(tmpdir.join('test'))
         makedirs(path)
-        with pytest.raises(Exception) as e_info:
-            makedirs(path, ignore_errors=False)
+        with pytest.raises(Exception):
+            makedirs(path, ignore_errors=False, exist_ok=False)
 
     def test_makedirs_with_mutl_dirs(self, tmpdir):
         path = str(tmpdir.join('test/test'))