Fundamentals of Python for Web App Penetration Testing

Let’s go through the fundamentals of Python to learn its basics.

Python generally comes pre-installed with Mac and Linux. For Windows, you need to install it on your own by visiting https://www.python.org/downloads. From here, download the latest version of Python and install it. 

• Running Code

Once installed, you can write the code in the terminal and run it. The code can also be saved as a file with py extension and can be run as a Python file. 

• Terminal

For simple commands, it is suggested to write and run the commands directly in the terminal. 

>>> shows that you are using the Python console. For instance, you can try it by writing a simple addition program:

>>> 4 + 3

It will give output as:

7

Write exit command to close the console:

>>> exit()

• Syntax

The syntax of Python is clean and simple. It doesn’t require unnecessary characters for showing specifications. For instance, it doesn’t use semicolons to end lines of code. 

To print a command, use the print() method. For instance:

print(‘command one’)

print(‘command two’)

Output: 

command one

command two

In the syntax, please note that Python is case-sensitive, which means that you need to take care of capital and small characters. For example, Name and name will act like two different variables. 

• Comments

For comments on a code, the # symbol is used. The role of using comments is to define what’s happening in a program. The comments don’t impact the program or its flow. 

• Variables

Variables are used to save and make changes to data for creating flow and logic. For example, a variable can be used to specify a name, another to store the age, etc. 

• Declaration

For the declaration of a variable, the process is simple. Just pick a name and assign a value with the use of = symbol. 

Hands on Python