Error while renaming files using os.rename()

Question

I am using python to rename files which exist as binary files but in actual are images. So I need to rename them into .jpg format. I am using os.rename() but getting the error:

Traceback (most recent call last):
  File "addext.py", line 8, in <module>
    os.rename(filename, filename + '.jpg')
OSError: [Errno 2] No such file or directory

Here's my code.

import os

for filename in os.listdir('/home/gpuuser/Aditya_Nigam/lum2/'):
    # print(filename + '.jpg')
    # k = str(filename)
    # print k
    # k = filename + '.jpg'
    os.rename(filename, filename + '.jpg')

print('Done')

Answer 1

os.listdir only return a list of filenames without their absolute paths, and os.rename will attempt to lookup a filename from the current directory unless given an absolute path. Basically, the code as-is will only work when executed in the same directory as the one called by os.listdir .

Consider doing the following:

import os
from os.path import join

path = '/home/gpuuser/Aditya_Nigam/lum2/'
for filename in os.listdir(path):
    os.rename(join(path, filename), join(path, filename) + '.jpg')

The os.path.join method will safely join the path with the filenames together in a platform agnostic manner.