OS Module in Python Programming

Modules in Python

What is OS Module in Python?

The os module contains functions that use the operating system dependent functionality to process operating system dependent tasks like creating a new directory, renaming a file, etc.

Many functions are available in the os module, but we will discuss only those that are frequently used in python programs.

os.name

The os.name returns the operating system's name on which we run our python code. The os name can be posix, nt, os2, ce, java, riscos.

import os

x = os.name
print(x)

nt

Here nt means we are running our python code on Microsoft Windows operating system.

os.listdir()

The os.listdir() function returns the list of all files and directories names present in a specified directory (folder).

import os

x = os.listdir(path='C:\Program Files (x86)\Python\Python38-32')
print(x)

['DLLs', 'Doc', 'include', 'Lib', 'libs', 'LICENSE.txt', 'NEWS.txt', 'python.exe', 'python3.dll', 'python38.dll', 'pythonw.exe', 'Scripts', 'tcl', 'Tools', 'vcruntime140.dll']
                                    

os.getcwd()

The os.getcwd() function returns the name of the current working directory. The current working directory is the directory from where we are running our python codes.

import os

x = os.getcwd()
print(x)

C:\Dremendo\PYTHON

In our case, we are running all our python codes from the directory given in the output.

os.chdir()

The os.chdir() function change the current working directory to a specified directory.

import os

x = os.getcwd()
print(x)
os.chdir('D:/templete')
x = os.getcwd()
print(x)

C:\Dremendo\PYTHON
D:\templete

os.mkdir()

The os.mkdir() function creates a new directory at a specified path. The specified path must exist to avoid an error.

import os

os.mkdir('D:/Data64/Alpha')
print('Directory Created Successfully')

Directory Created Successfully

In the above example, the Data64 directory must exist at D:\ drive to create the Alpha directory.

os.makedirs()

The os.makedirs() function creates a new directory at a specified path. If the specified path does not exist, then the os.makedirs() function will create it.

import os

os.makedirs('D:/Data64/Alpha/Beta')
print('Directory Created Successfully')

Directory Created Successfully

In the above example, if the Data64 directory does not exist at D:\ drive, then the os.makedirs() function will create the Data64 and all its sub-directories.

os.rename()

The os.rename() function is used to rename a file or directory. The rename() function takes two arguments: the path of the file or directory to be renamed and the new name for the file or directory along with its full path.

import os

os.rename('D:/Data64/Alpha/Beta/delta.txt','D:/Data64/Alpha/Beta/record.txt')
print('File Renamed Successfully')
os.rename('D:/Data64/Alpha/Beta','D:/Data64/Alpha/Data')
print('Directory Renamed Successfully')

File Renamed Successfully
Directory Renamed Successfully

os.remove()

The os.remove() function deletes a specified file. The specified file must exist to avoid an error.

import os

os.remove('D:/Data64/Alpha/Data/record.txt')
print('File Deleted Successfully')

File Deleted Successfully

os.rmdir()

The os.rmdir() function deletes an empty directory. The function will raise an error if the directory is not empty.

import os

os.rmdir('D:/Data64/Alpha/Data')
print('Directory Deleted Successfully')

Directory Deleted Successfully

Note: To delete a directory, whether empty or not empty, we can use the function shutil.rmtree(). See the example given below.

import shutil

shutil.rmtree('D:/Data64')
print('Directory Deleted Successfully')

Directory Deleted Successfully

os.system()

The os.system() function executes the system commands.

import os

os.system('date')

The current date is: 30-Aug-22
Enter the new date: (dd-mm-yy)

The above program will execute the date command in the command prompt of the Windows operating system.

Note: We can also clear our console screen in python using the system command cls for windows operating system and clear for Linux and Mac operating systems.

import os

os.system('cls')

The above program will clear the console screen in python under the Windows operating system.

os.startfile()

The os.startfile() function runs or open a file with its default associated application. For example, a microsoft word file will be opened using Microsoft Word application.

import os

os.startfile('D:/Accountancy.pdf')

The above program opened the pdf file Accountancy.pdf, which is in our D: drive.

os.path.basename()

The os.path.basename() function returns the basename of a specified path. The right-most name in a specified path is called the basename.

import os

x = os.path.basename('D:/MySQL/bin/mysql.exe')
y = os.path.basename('D:/MySQL/bin')

print('Path = D:/MySQL/bin/mysql.exe')
print('Basename = %s' %(x))
print('Path = D:/MySQL/bin')
print('Basename = %s' %(y))

Path = D:/MySQL/bin/mysql.exe
Basename = mysql.exe
Path = D:/MySQL/bin
Basename = bin

os.path.dirname()

The os.path.dirname() function returns the full directory path after excluding the basename from the specified path.

import os

x = os.path.dirname('D:/MySQL/bin/mysql.exe')
y = os.path.dirname('D:/MySQL/bin')

print('Path = D:/MySQL/bin/mysql.exe')
print('Directory path = %s' %(x))
print('Path = D:/MySQL/bin')
print('Directory path = %s' %(y))

Path = D:/MySQL/bin/mysql.exe
Directory path = D:/MySQL/bin
Path = D:/MySQL/bin
Directory path = D:/MySQL

os.path.exists()

The os.path.exist() function returns true if the specified path exists. If the specified path does not exist, then it returns false.

import os

x = os.path.exists('D:/MySQL/bin/mysql.exe')
y = os.path.exists('D:/MySQL/bin/data')

print('Path = D:/MySQL/bin/mysql.exe')
print('mysql.exe file exist = %s' %(x))
print('Path = D:/MySQL/bin/data')
print('data directory exist = %s' %(y))

Path = D:/MySQL/bin/mysql.exe
mysql.exe file exist = True
Path = D:/MySQL/bin/data
data directory exist = False