user.py -- when imported, execfile(~/.pythonrc.py).

Lib/user.py

+"""Hook to allow user-specified customization code to run.
+
+As a policy, Python doesn't run user-specified code on startup of
+Python programs (interactive sessions execute the script specified in
+the PYTHONPATH environment variable if it exists).
+
+However, some programs or sites may find it convenient to allow users
+to have a standard customization file, which gets run when a program
+requests it.  This module implements such a mechanism.  A program
+that wishes to use the mechanism mist execute the statement
+
+    import user
+
+The user module looks for a file .pythonrc.py in the user's home
+directory and if it can be opened, execfile()s it in its own global
+namespace.  Errors during this phase are not caught; that's up to the
+program that imports the user module, if it wishes.
+
+The user's .pythonrc.py could conceivably test for sys.version if it
+wishes to do different things depending on the Python version.
+
+"""
+
+import os
+
+try:
+    home = os.environ['HOME']
+except:
+    home = os.curdir
+
+pythonrc = os.path.join(home, ".pythonrc.py")
+try:
+    f = open(pythonrc)
+except IOError:
+    pass
+else:
+    f.close()
+    execfile(pythonrc)