add check_for_old_config to warn users about old config files, and point them to new ones

closes gh-304

IPython/frontend/terminal/ipapp.py

@@ -37,7 +37,7 b' from IPython.config.loader import ('
     PyFileConfigLoader
 )
 from IPython.lib import inputhook
-from IPython.utils.path import filefind, get_ipython_dir
+from IPython.utils.path import filefind, get_ipython_dir, check_for_old_config
 from IPython.core import usage
 
 #-----------------------------------------------------------------------------
@@ -635,6 +635,7 b' class IPythonApp(Application):'
                 self.shell.showtraceback()
 
     def start_app(self):
+        check_for_old_config(self.ipython_dir)
         if self.master_config.Global.interact:
             self.log.debug("Starting IPython's mainloop...")
             self.shell.mainloop()

IPython/utils/path.py

@@ -18,6 +18,7 b' import os'
 import sys
 
 import IPython
+from IPython.utils import warn
 from IPython.utils.process import system
 from IPython.utils.importstring import import_item
 
@@ -399,3 +400,22 b' def target_update(target,deps,cmd):'
     if target_outdated(target,deps):
         system(cmd)
 
+def check_for_old_config(ipython_dir=None):
+    """Check for old config files, and present a warning if they exist.
+
+    A link to the docs of the new config is included in the message.
+
+    This should mitigate confusion with the transition to the new
+    config system in 0.11.
+    """
+    if ipython_dir is None:
+        ipython_dir = get_ipython_dir()
+
+    old_configs = ['ipy_user_conf.py', 'ipythonrc']
+    for cfg in old_configs:
+        f = os.path.join(ipython_dir, cfg)
+        if os.path.exists(f):
+            warn.warn("""Found old IPython config file %r.
+    The IPython configuration system has changed as of 0.11, and this file will be ignored.
+    See http://ipython.github.com/ipython-doc/dev/config for details on the new config system.
+    The current default config file is 'ipython_config.py'"""%f)