Python

Resources

https://www.codecademy.com/learn/learn-python-3/modules/learn-python3-syntax/cheatsheetwww.codecademy.com

Create and execute the script

touch python101.py
chmod u+x python101.py
nano python101.py
#!/usr/bin/env python3
python3 python101.py

Print

#Print String

print("Strings and things:")
print('Hello, world!')
print("""Hello, this is
a multiline string :)""")
print("This is"+" a string")

print ('\n') #new line

Math

print(50 + 50) #add --> 100                               
print(50 - 50) #substract --> 0
print(50 * 50) #multiply --> 2500
print(50 / 50) #divide --> 1.0
print(50 ** 2) #exponents --> 2500
print(50 % 6) #modulo --> 2
print(50 // 6) #number without leftovers  --> 8

numb = -5
print(abs(numb)) # 5

print(pow(3,2)) # 3 square 2 = 9
print(max(5,8)) # highest number : 8
print(min(5,8)) # smallest number : 5
print(round(4.2)) # 4
print(round(4.7)) #5

--------------------------------

from math import *
print(floor(4.2)) #print 4
print(ceil(4.2)) #print 5
print(sqrt(36))  #print 6

Variables & Methods

quote = “All is fair in love and war”
print(len(quote)) #length
print(quote.upper()) #uppercase  -->   ALL IS FAIR IN LOVE AND VAR
print(quote.lower()) #lowercase  -->   all is fair in love and var
print(quote.title()) #title     -->   All Is Fair In Love And Var
print(quote.isupper()) #return false
print(quote.upper().isupper()) #return true
print(quote.index("is")) #4 (start index to 0)

name = “Protyro”
age = 23   #int
demi = 0.5 #float 

print(int(age))
print(int(27.6)) # don't work

print("My name is " + name + " and I am " + str(age) + " years old.")

age += 1
print(age)          ← 24 (23+1)

birthday = 1
age += birthday
print(age)          ← 25 (23+1+1)

Getting Input From Users

name = input("Please enter your name : ") # input type is string by default for py3
age = input("Please enter your age : ")
print("Hello " + name + " !")
print("You are " + age + " years old.")

Functions

#Functions

print ("Here is an example function")

def who_am_i(): #this is a function
        name = "Protyro"
        age = 23
        print("My name is " + name + " and I am " + str(age) + " years old.")

who_am_i()

#adding parameters

def add_one_hundred(number):
        print(number + 100)

add_one_hundred(100)

#multiple parameters

def add(x,y):
        print(x + y)

add(7,7)

def multiply(x,y):
        return x * y

print(multiply(8,9))

def square_root(x):
        print(x ** .5)

square_root(64)

def nl():
        print('\n')

nl()

Boolean expressions

#Boolean expressions (True or False)

print("Boolean expressions:")

bool1 = True
bool2 = 3*3 == 9
bool3 = False
bool4 = 3*3 != 9

print(bool1,bool2,bool3,bool4)
print(type(bool1))

Relational & boolean operators

#Relational & Boolean operators

greater_than = 7 > 5
less_than = 5 < 7
greater_than_equal_to = 7 >= 7
less_than_equal_to = 7 <= 7

test_and = (7 > 5) and (5 < 7) #True
test_and2 = (7 > 5) and (5 > 7) #False because 5 is not greater than 7
test_or = (7 > 5) or (5 < 7) #True
test_or2 = (7 > 5) or (5 > 7) #True

test_not = not True #False

Conditional statements

def drink(money):
        if money >= 2:
                return "You've got yourself a drink"
        else:
                return "No drink for you"

print(drink(3))
print(drink(1))

def alcohol(age,money):
        if (age >= 21) and (money >= 5):
                return "We're getting a drink !"
        elif (age >= 21) and (money < 5):
                return "Come back with more money"
        elif (age < 21) and (money >= 5):
                return "Nice try kid"
        else:
                return "You're too poor and too young"

print(alcohol(21,5))
print(alcohol(21,4))
print(alcohol(20,4))

Lists

#Lists - Have brackets []

movies = ["Interstellar", "Inception", "Avengers", "Joker"]

print(movies[1]) #return the second item
print(movies[0]) #return first item of the list
print(movies[1:3]) #range start with 1 and end before 3 (2)
print(movies[1:]) # print all the list and start with item 1
print(movies[:1]) # start with item 0 and end at item 1
print(movies[-1]) # grab the last item

print(len(movies)) #print the numbers item
movies.append("Tu ne tueras point") # add a film to the list
print(movies)

movies.pop() #remove the last item
print(movies)

movies.pop(0) #remove the first item 
print(movies)

movies.sort()
movies.reverse()

numbers = [1, 2, 3, 4, 6]
numbers.insert(4,5) # add number 5 after the 4
movies.extend(numbers)
print(movies) # numbers were added to movies list

moviesAndNumbers = movies.copy()

movies.clear()

Tuples

#Tuples - Do not change, ()

grades = ("a","b","c","d","e","f")
print(grades[1]) # print b

Looping

#Looping

# For loops - start to finish an iterate

vegetables = ["cucumber","spinach","cabbage"]
for x in vegetables:
	print(x)
	
for i in range(1,10): # First parameter is the start point and the second is the end point
	print(i)

for i in range(0,20,2): # The third parameter tell the program how much to increment
	print(i)
else :
	print("Finish") #We can add an else statement at the end
		
# While loops - Execute as long as true

i = 1
while i < 10:
	print(i)
	i += 1
	
while True:
	print("spam")

Importing modules

import sys # sys is system functions and parameters
from datetime import datetime as dt # import with alias

print(sys.version)
print(dt.now())

Advanced strings

# Advanced Strings

my_name = "Protyro"
print(my_name[0]) #P
print(my_name[-1])#o

sentence = "This is a sentence."
print(sentence[:4]) # Print "This"
print(sentence[-4:]) # Print nce.
print(sentence.split()) # Split at each space
print(type(sentence.split())) # This is a list

print(sentence.replace("sentence","quote")

sentence_split = sentence.split()
sentence_join = ' '.join(sentence_split)
print(sentence_join)

quote = "He said, 'give me all your money'"
quote2 = "He said, \"give me all your money\""
print(quote)
print(quote2)

too_much_space = "                 hello     "
print(too_much_space.strip()) #remove space

print("a" in "Apple")
print("A" in "Apple")

nl()

letter = "A"
word = "Apple"
print(letter.lower() in word.lower()) # Search "a" in "apple" and return true

movie = "Interstellar"
print("My favorite movie is {}.".format(movie))

Dictionaries

# Dictionaries - Key/value pairs {}

drinks = {"Ice tea": 3, "Coca": 4, "Fanta": 2} # Drink is the key, price is the value
print(drinks)

employees = {"Finance": ["Bob", "Linda", "Tina"], "IT":["Alex", "Julien", "Seb"], "HR": ["Barbara", "Alice", "Julianne"]}
print(employees)

employees['Legal'] = ["Franck"] #add new key:value pair
print(employees)

employees.update({"Sales": ["Kevin", "Romain"]}) #add new key:value pair
print(employees)

drinks['Coca'] = 5
print(drinks)
print(drinks.get("Coca")) # Return the value (the price here)

Sockets

#Sockets

import socket

HOST = '127.0.0.1'
PORT = 7777

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) #AF_NET is ipv4 & SOCK_STREAM is the port
s.connect((HOST,PORT))

Files

file = open("/path/file.txt","r")
print(file.read(5)) #print 5 caracters
print(file.readlines()) #print each line
print(file.readline()) #print a single line, can be invoked multiple times

for line in file:
    print(line, end='')

#File mode :
#r -read / w -write /a -append / r+ -read and write
#There is more file modes not listed here

#-----------------------
file = open("test.txt","w")
file.write("This is a test") #overwrite

Virtual environment

sudo apt install virtualenv
virtualenv --python=python3 EnvironmentName
source EnvironmentName/bin/activate
deactivate

PIP

sudo apt install python3-pip
pip3 install pwntools
pip3 install -r requirements.txt

-----------------------

from pwn import *

Script example - Port scanner

#!/bin/python3

import sys
import socket
from datetime import datetime

#Define our target

if len(sys.argv) == 2:
	target = socket.gethostbyname(sys.argv[1]) # Translate hostname to ipv4
else:
	print("Invalid amount of arguments.")
	print("Syntax: python3 scanner.py <ip>")

#Add a pretty banner

print("-" * 50)
print("Scanning target " + target)
print("Time started: "+str(datetime.now()))
print("-" * 50)

try:
	for port in range(1,100): #(1,65535)
		s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
		socket.setdefaulttimeout(1)
		result = s.connect_ex((target, port)) # Return 0 if port is open, 1 otherwise
		#print("Checking port {}...".format(port))
		if result == 0:
			print("Port {} is open".format(port))
		s.close()

except KeyboardInterrupt:
	print("\nExiting program.")
	sys.exit()

except socket.gaierror:
	print("Hostname could not be resolved.")
	sys.exit()

except socket.error:
	print("Could connect to ip address.")
	sys.exit()