Fchmod() Function Of Os Module In Python

Function Name:


Function Signature:

fchmod(fd, mode)


  • Given a file descriptor, the function fchmod() of os module in Python changes the permissions of the associated file. To change file permissions using only a file path, instead of a file descriptor the os.chmod() function to be used.


fd - File descriptor. Note that this is not the file object as returned by the built-in function open(). It has to be a descriptor as returned by the function like os.open().

mode - One or more file permissions bitwise ORed

Return Value:



# Example Python program that changes the permissions
# for a file through its file descriptor using
# the os.fchmode() function
import os
import stat

# File for which the permissions need to be changed
fileDescritor    = os.open("/PythonProgs/test.txt", os.O_RDWR)
filePermissions = stat.S_IRWXU | stat.S_IRGRP | stat.S_IXOTH

# Change the file permissions
os.fchmod(fileDescritor, filePermissions)


Though the above program does not print anything issuing an ls -l on the test.txt prints the following, that shows the new file permissions for test.txt.


mymac:PEX usr1$ ls -l test.txt
-rwxr----x  1 root  wheel  0 Mar 30 13:59 test.txt


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