What is sys in Python

The Python sys module provides easy functions that allow us to interact with the interpreter directly. It lets us access system-specific parameters and functions.

First, we have to import the sys module in our program before running any functions.

import sys

sys.modules

This function provides the name of the existing python modules which have been imported.

sys.argv

This function returns a list of command line arguments passed to a Python script. The name of the script is always the item at index 0, and the rest of the arguments are stored at subsequent indices.

import sys
print('The command line arguments are:')
for i in sys.argv:
    print(i)

sys.base_exec_prefix

This function provides an efficient way to the same value as exec_prefix. If not running a virtual environment, the value will remain the same.

sys.base_prefix

It is set up during Python startup, before site.py is run, to the same value as prefix.

sys.byteorder

It is an indication of the native byteorder that provides an efficient way to do something.

sys.maxsize

This function returns the largest integer of a variable.

sys.path

This function shows the PYTHONPATH set in the current system. It is an environment variable that is a search path for all the python modules.

>>> import sys
>>> sys.path
['', 'C:\\Users\\user\\AppData\\Local\\Programs\\Python\\Python38\\python38.zip', 'C:\\Users\\user\\AppData\\Local\\Programs\\Python\\Python38\\DLLs', 'C:\\Users\\user\\AppData\\Local\\Programs\\Python\\Python38\\lib', 'C:\\Users\\user\\AppData\\Local\\Programs\\Python\\Python38', 'C:\\Users\\user\\AppData\\Roaming\\Python\\Python38\\site-packages', 'C:\\Users\\user\\AppData\\Local\\Programs\\Python\\Python38\\lib\\site-packages', 'C:\\Users\\user\\AppData\\Local\\Programs\\Python\\Python38\\lib\\site-packages\\win32', 'C:\\Users\\user\\AppData\\Local\\Programs\\Python\\Python38\\lib\\site-packages\\win32\\lib', 'C:\\Users\\user\\AppData\\Local\\Programs\\Python\\Python38\\lib\\site-packages\\Pythonwin']
>>>

sys.stdin

It is an object that contains the original values of stdin at the start of the program and used during finalization. It can restore the files.

sys.getrefcount

This function returns the reference count of an object.

sys.exit

This function is used to exit from either the Python console or command prompt, and also used to exit from the program in case of an exception.

sys executable

The value of this function is the absolute path to a Python interpreter. It is useful for knowing where python is installed on someone else machine.

sys.platform

This value of this function is used to identify the platform on which we are working.