import os
oldFileName = "test.txt"
newFileName = "test.old"
for file in os.listdir("c:/"):
if file.startswith("output"):
print file
if os.access(newFileName, os.X_OK):
print "Removing " + newFileName
os.remove(newFileName)
os.rename(oldFileName, newFileName)
for file in os.listdir("c:/"):
if file.startswith("output"):
print file