Day-5 | Command Line Args & Env Vars | Most Simple Explanation #python #abhishekveeramalla

Introduction

This tutorial will guide you through understanding command line arguments and environment variables in Python, as presented in the video by Abhishek Veeramalla. These concepts are essential for developing flexible and dynamic applications that can adapt based on user input or system configuration.

Step 1: Understanding Command Line Arguments

Command line arguments allow users to pass input to a Python script from the terminal.

• Accessing Command Line Arguments:

  • Use the sys module to access these arguments.

  import sys
  
  # Access command line arguments
  args = sys.argv
  print(args)
  

  • sys.argv is a list where the first element is the script name, followed by any additional arguments.

• Practical Usage:

  • You can use command line arguments to customize script behavior. For example, if you are writing a script that processes files, you might pass the filename as an argument.

Step 2: Using Environment Variables

Environment variables are key-value pairs available in your operating system that can be accessed by your applications.

• Accessing Environment Variables:

  • Use the os module in Python to read environment variables.

  import os
  
  # Get an environment variable
  path = os.getenv('PATH')
  print(path)
  

  • The os.getenv() function retrieves the value of the specified environment variable.

• Setting Environment Variables:

  • While you can set environment variables in the terminal, it's often done via scripts or configuration files depending on your operating system.

• Practical Usage:

  • Environment variables are useful for storing sensitive information such as API keys or configuration settings that should not be hard-coded in your scripts.

Step 3: Combining Command Line Arguments and Environment Variables

You can combine both command line arguments and environment variables in your scripts for enhanced flexibility.

• Example Usage:

  • Create a script that takes a filename as a command line argument and reads a specific environment variable to determine file processing settings.

  import sys
  import os
  
  # Command line argument for filename
  filename = sys.argv[1]
  
  # Environment variable for processing type
  processing_type = os.getenv('PROCESSING_TYPE', 'default')
  
  print(f'Processing {filename} with {processing_type} settings.')
  

Conclusion

In this tutorial, you learned how to use command line arguments and environment variables in Python. These tools allow for greater flexibility in your scripts, making them more dynamic and adaptable to different environments or user inputs. As you continue your Python journey, consider how these concepts can be applied in your projects, especially in DevOps and cloud environments. For further learning, explore the provided resources and practice creating scripts that utilize these features effectively.