Introduction to Python 3

Welcome to Introduction to Python 3. This module will cover most of the essentials you need to know to get started with Python scripting. Whether you have a background in IT or just starting, this module will attempt to guide you through the process of creating small but useful scripts. This module will present to you an amount of code that will, depending on your previous experience, seem just enough or quite a lot. But fear not, we will get through this together.

So why even learn Python, one might ask? Python is one of the most popular scripting languages currently. This makes it a popular choice for automation of everyday tasks or the development of tools. In the InfoSec world, plenty of so-called PoCs (Proof of Concepts) are written in Python, as are many popular tools for penetration testing. The simplicity of the language makes it appealing to use when a need to "just write something quickly" arises. Yet, the language's flexibility and community support also make it a perfect candidate for larger projects. Whether you need to write a simple script that will automate a repetitive task on a website, crawling or analyzing large amounts of data, performing buffer overflow attacks, creating an interactive service, or something completely different, Python makes development easy.

Python is an interpreted language, which means the code itself is not compiled into machine code like C code. Instead, it is interpreted by the Python program, and the instructions in the script(s) are executed. Python is a high-level language meaning the scripts we produce are simplified for our convenience so that we do not need to worry about memory management, system calls, and so forth. Furthermore, Python is a general-purpose, multi-paradigm language that is a fancy way of saying "you can use it for most things with ease" and "it doesn't mind if you prefer one style or another."

As for the coding style, we will gently touch on the object-oriented style because this makes reasoning about code a lot simpler. Essentially, object-oriented programming will likely feel less intimidating if you've ever played with either blocks or bricks of either digital or physical form. Lastly, Python is rumored to be easy to read, especially in the beginning. This may be because of its close resemblance to the English language and its strict requirements for proper code indentation.

In this module, there will be code examples and lots of them. It is highly recommended that you type out all of the code by hand as you read along and refrain from copying and pasting. This will help you get in the flow and will help you remember what you learned. It is also highly recommended to explore and play around with the tools and techniques taught in this module. It is assumed that Python 3 is already installed on your system and that the Python 3 executable is in the PATH. A web-based virtual machine with Python 3 already installed and configured properly will be provided for all relevant sections.

Once again, welcome to the module.