Rename multiple files in a directory in Python

The following code should work. It takes every filename in the current directory, if the filename contains the pattern CHEESE_CHEESE_ then it is renamed. If not nothing is done to the filename.

import os
for fileName in os.listdir("."):
    os.rename(fileName, fileName.replace("CHEESE_CHEESE_", "CHEESE_"))

Use os.rename(src, dst) to rename or move a file or a directory.

$ ls
cheese_cheese_type.bar  cheese_cheese_type.foo
$ python
>>> import os
>>> for filename in os.listdir("."):
...  if filename.startswith("cheese_"):
...    os.rename(filename, filename[7:])
... 
>>> 
$ ls
cheese_type.bar  cheese_type.foo

Here's a script based on your newest comment.

#!/usr/bin/env python
from os import rename, listdir

badprefix = "cheese_"
fnames = listdir('.')

for fname in fnames:
    if fname.startswith(badprefix*2):
        rename(fname, fname.replace(badprefix, '', 1))