Python | os.fchmod () method

Michael Zippo

On Unix-like systems, the modes — these are the file system permissions granted to users, groups, and other classes to access the file.
os.fchmod() in Python is used to change the file mode specified by the specified file descriptor to the specified numeric mode. This method is equivalent to os.chmod (fd, mode) .

Note. This the method is only available on Unix platforms.

Syntax: os.fchmod (fd, mode)

Parameters:
fd: A file descriptor whose mode is to be set.
mode: A numeric value representing mode to be set.
mode may also take one of the following values or bitwise ORed combinations of them:

stat.S_ISUID: Set user ID on execution

stat.S_ISGID: Set group ID on execution

stat.S_ENFMT: Record locking enforced

stat.S_ISVTX: Save text image after execution

stat.S_IREAD: Read by owner.

stat.S_IWRITE : Write by owner.

stat.S_IEXEC: Execute by owner.

stat.S_IRWXU: Read , write, an d execute by owner

stat.S_IRUSR: Read by owner

stat.S_IWUSR: Write by owner.

stat.S_IXUSR: Execute by owner.

stat.S_IRWXG: Read, write, and execute by group

stat.S_IRGRP: Read by group

stat.S_IWGRP: Write by group

stat.S_IXGRP : Execute by group

stat.S_IRWXO: Read, write, and execute by others.

stat.S_IROTH: Read by others

stat.S_IWOTH: Write by others

stat.S_IXOTH: Execute by others

Return type: This method does not return any value.

Code: using the os method .fchmod ()

# Python program to explain os.fchmod () method definitions

# import of the os module

import os

# import of statistics module

import stat

# Filename

filename = "file.txt"

# Open the specified file and
# get file descriptor
# related with this
# os.open () method

fd = os. open (filename, os.O_RDWR)

# Print the current numeric mode
# (octal) file

mode = oct (os.stat (fd) .st_mode) [ - 3 :]

print ( "Current numeric mode of the file (octal notation):" , mode)

# Now change the mode
File #

# octal 777 as mode value
# read, write and execute permission
# for owner, group and others

mode = 0o777

os.fchmod (fd, mode)

print ( "File mode changed successfully" )

# Print changed numeric mode
# (octal) file

mode = oct (os.stat (fd) .st_mode) [ - 3 :]

print ( "Current numeric mode of the file (octal notation):" , mode)

The # mode parameter can also be
# defined by flags defined in
# Stat module

# Chnage mode

mode = stat.S_IRWXU

os.fchmod (fd, mode)

print ( "File mode changed successfully" )

print ( "Now, File can be read, write and execute d by owner only " )

# Print modified numeric mode
# (octal) of file

mode = oct (os.stat (fd) .st_mode) [ - 3 :]

print ( "Current numeric mode of the file (octal notation):" , mode)

# change mode

mode = stat.S_IRWXU | stat.S_IRGRP

os.fchmod (fd, mode)

print ( "File mode changed successfully" )

print ("Now, File can be read, write and executed

by owner but can be read by group ")

# Print modified numeric mode
# (octal) file

mode = oct (os.stat (fd) .st_mode) [ - 3 :]

p rint ( "Current numeric mode of the file (octal notation):" , mode)

# Close the file descriptor
os.close (fd)

Exit :

 Current numeric mode of the file (octal notation): 666 File mode changed successfully Current numeric mode of the file (octal notation): 777 File mode changed successfully Now, File can be read, write and executed by owner only Current numeric mode of the file (octal notation): 700 File mode changed successfully Now, File can be read , write and executed by owner but can be read by group Current numeric mode of the file (octal notation): 740