Python | os.write() method

OS module in Python provides functions for interacting with the operating system. OS comes under Python’s standard utility modules. This module provides a portable way of using operating system dependent functionality.

os.write() method in Python is used to write a bytestring to the given file descriptor.

A file descriptor is small integer value that corresponds to a file that has been opened by the current process. It is used to perform various lower level I/O operations like read, write, send etc.

Note: os.write() method is intended for low-level operation and should be applied to a file descriptor as returned by os.open() or os.pipe() method.

Syntax: os.write(fd, str)

Parameter:
fd: The file descriptor representing the target file.
str: A bytes-like object to be written in the file.

Return Type: This method returns an integer value which represents the number of bytes actually written.

Code: Use of os.write() method to write a bytestring to a given file descriptor

# Python program to explain os.write() method

# importing os module
import os

# File path
path = "/home / ihritik / Documents / GeeksForGeeks.txt"


# Open the file and get
# the file descriptor associated
# with it using os.open() method
fd = os.open(path, os.O_RDWR)


# String to be written
s = "GeeksForGeeks: A Computer science portal for Geeks."

# Convert the string to bytes
line = str.encode(s)

# Write the bytestring to the file
# associated with the file
# descriptor fd and get the number of
# Bytes actually written
numBytes = os.write(fd, line)

print("Number of bytes written:", numBytes)

# close the file descriptor
os.close(fd)

Output:

Number of bytes written: 51