Python 3 - os.dup() Method

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Description

The method dup() returns a duplicate of file descriptor fd which can be used in place of original descriptor.

Syntax

Following is the syntax for dup() method −

os.dup(fd)

Parameters

fd − This is the original file descriptor.

Return Value

This method returns a duplicate of file descriptor.

Example

The following example shows the usage of dup() method.

#!/usr/bin/python3
import os, sys

# Open a file
fd = os.open( "foo.txt", os.O_RDWR|os.O_CREAT )

# Get one duplicate file descriptor
d_fd = os.dup( fd )

# Write one string using duplicate fd
line = "this is test" 

# string needs to be converted byte object
b = str.encode(line)
os.write(d_fd, b)

# Close a single opened file
os.closerange( fd, d_fd)

print ("Closed all the files successfully!!")

Result

When we run the above program, it produces the following result −

Closed all the files successfully!!