diff --git a/PRESUBMIT.py b/PRESUBMIT.py
index ff218b34e5..d79c1a7d71 100644
--- a/PRESUBMIT.py
+++ b/PRESUBMIT.py
@@ -25,6 +25,7 @@ def CheckChangeOnUpload(input_api, output_api):
                                                            output_api,
                                                            UNIT_TESTS))
   output.extend(WasGitClUploadHookModified(input_api, output_api))
+  output.extend(RunPylint(input_api, output_api))
   return output
 
 
@@ -36,6 +37,7 @@ def CheckChangeOnCommit(input_api, output_api):
   output.extend(input_api.canned_checks.CheckDoNotSubmit(input_api,
                                                          output_api))
   output.extend(WasGitClUploadHookModified(input_api, output_api))
+  output.extend(RunPylint(input_api, output_api))
   return output
 
 def WasGitClUploadHookModified(input_api, output_api):
@@ -46,3 +48,16 @@ def WasGitClUploadHookModified(input_api, output_api):
           'Don\'t forget to fix git-cl to download the newest version of '
           'git-cl-upload-hook')]
   return []
+
+def RunPylint(input_api, output_api):
+  import glob
+  files = glob.glob('*.py')
+  # It's a python script
+  files.append('git-try')
+  # It uses non-standard pylint exceptions that makes pylint always fail.
+  files.remove('cpplint.py')
+  proc = input_api.subprocess.Popen(['pylint', '-E'] + files)
+  proc.communicate()
+  if proc.returncode:
+    return [output_api.PresubmitError('Fix pylint errors first.')]
+  return []
diff --git a/chrome-update.py b/chrome-update.py
index 6398230542..a2baa43c52 100755
--- a/chrome-update.py
+++ b/chrome-update.py
@@ -133,7 +133,7 @@ def Main():
                     help="doesn't sync before building")
   parser.add_option("", "--print-latest", action="store_true", default=False,
                     help="print the latest buildable revision and exit")
-  options, args = parser.parse_args()
+  options, args = parser.parse_args(None)
 
   if options.print_latest:
     print GetRevision() or "HEAD"
diff --git a/drover.py b/drover.py
index 77922cd705..9329fda2b6 100755
--- a/drover.py
+++ b/drover.py
@@ -402,11 +402,9 @@ def drover(options, args):
   # Override the default properties if there is a drover.properties file.
   global file_pattern_
   if os.path.exists("drover.properties"):
-    f = open("drover.properties")
-    exec(f)
-    f.close()
-    if FILE_PATTERN:
-      file_pattern_ = FILE_PATTERN
+    FILE_PATTERN = file_pattern_
+    execfile("drover.properties")
+    file_pattern_ = FILE_PATTERN
 
   if options.revert and options.branch:
     url = BRANCH_URL.replace("$branch", options.branch)
diff --git a/presubmit_support.py b/presubmit_support.py
index f0676c65fa..c03c3eabf3 100755
--- a/presubmit_support.py
+++ b/presubmit_support.py
@@ -588,18 +588,18 @@ class Change(object):
 
     # From the description text, build up a dictionary of key/value pairs
     # plus the description minus all key/value or "tag" lines.
-    self._description_without_tags = []
+    description_without_tags = []
     self.tags = {}
     for line in self._full_description.splitlines():
       m = self._TAG_LINE_RE.match(line)
       if m:
         self.tags[m.group('key')] = m.group('value')
       else:
-        self._description_without_tags.append(line)
+        description_without_tags.append(line)
 
     # Change back to text and remove whitespace at end.
-    self._description_without_tags = '\n'.join(self._description_without_tags)
-    self._description_without_tags = self._description_without_tags.rstrip()
+    self._description_without_tags = (
+        '\n'.join(description_without_tags).rstrip())
 
     self._affected_files = [
         self._AFFECTED_FILES(info[1], info[0].strip(), self._local_root)