Python OS File/Directory os.dup() Method

Description

The dup() method returns a copy of the file descriptor fd, which can be used instead of the original descriptor.

Syntax

The syntax of the dup() method is as follows:

os.dup(fd)

Parameters

• fd – This is the original file descriptor.

Return Value

This method returns a copy of the file descriptor.

Example

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

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 to a 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!!")

When we run the above program, it produces the following output:

Closed all the files successfully!