Python os.dup() Method

1. Syntax of Python os.dup():
2. Example Code: Use the os.dup() Method to Duplicate a File Descriptor

The dup() method belongs to the os module. The os module contains implementations for various functions to communicate and work with the operating system. The dup() method returns a duplicate for a file descriptor.

Syntax of Python os.dup():

os.dup(fd)

Parameter

Return

The dup() method returns a duplicate for a file descriptor. Note that the new file descriptor is non-inheritable. Non-inheritable means that the file descriptor created can not be inherited by the child processes. In child processes, all the non-inheritable file descriptors are closed.

Example Code: Use the os.dup() Method to Duplicate a File Descriptor

import os

path = "a.txt"
f1 = os.open(path, os.O_RDONLY)
fcopy = os.dup(f1)
print(f1)
print(fcopy)
os.close(f1)

Output:

3
4

As we can conclude from the output, the two file descriptors are different, and the dup() method created a hard copy of the original file descriptor.