--- a/checker.py	Sat Jul 16 19:05:11 2016 +0800
+++ b/checker.py	Sat Jul 16 21:07:54 2016 +0800
@@ -176,8 +176,11 @@
 
     print('# C&O task: setup')
 
-    to_install = [l['name'] for l in config.get('linters', []) if 'name' in l]
-    print('# C&O linters to install: {}'.format(' '.join(to_install)))
+    requested = []
+    for linter in config.get('linters', []):
+        if 'name' in linter and linter['name'] not in requested:
+            requested.append(linter['name'])
+    print('# C&O linters requested: {}'.format(' '.join(requested)))
 
     linter_config = {}