Python Classroom notes 10/Apr/2026

Sys module

• This is a built in library that provides variables and functinons to interact with the pytho runtime environment an interpreter

Commonly use features in sys module

Command-line arguments:

sys.argv => complete arguments
sys.argv[0] => script or python module
sys.argv[1:] => remaining arguments

• Consider the following python code

import sys

print(f"complete argv {sys.argv}")

print(f"script: {sys.argv[0]}")

print(f"args: {sys.argv[1:]}")

• Lets explore by running this
  

Exiting a Script

• Exiting as script sys.exit()
• 0 => success code and any other number is conisdered as failure

import sys

if (len(sys.argv) < 2):
    sys.exit(1)

sys.exit(0)

module search path

• sys.path is a list of strings that specifies where the python interpreter should look when you try to import a module

• for others refer this notebook Refer Here

Lets build a todo list application

• Think of this as a small to-do list or a sticky-notes
• Except the paper is a plain text file.

• this will be a cli application which does following

  • add task
  • list tasks
  • remove/complete task

• Refer Here for the changes

Adding additional behaviors

• To be discussed later