Table of Contents

  1. Introduction to Bash and Python Scripting
  2. Bash Scripting Basics
    1. Basic Syntax and Variables
    2. File Management
    3. Environment Variables and Permissions
    4. Command-Line Arguments and Loops
    5. Networking and System Monitoring
  3. Python Scripting Basics
    1. Essential Modules for Cybersecurity
    2. Working with Files and Directories
    3. Network Operations with socket
    4. Automating with subprocess
    5. Handling JSON and YAML Configuration Files
  4. Intermediate Scripting Techniques
    1. Error Handling and Validation
    2. Logging and Timestamping
    3. Argument Parsing
  5. Advanced Scripting for Cybersecurity
    1. Port Scanners
    2. File Integrity Checkers
    3. Activity and Intrusion Detection
  6. Best Practices for Cybersecurity Scripts
    1. Shebang and File Permissions
    2. Virtual Environments
    3. Code Readability and Comments
  7. Glossary
  8. Further Reference Examples

1. Introduction to Bash and Python Scripting

Scripting is a cornerstone of cybersecurity operations, enabling automation of tasks like network scanning, log analysis, and system monitoring. Bash provides simplicity and direct OS interaction, while Python adds flexibility and power for complex workflows.

2. Bash Scripting Basics

2.1 Basic Syntax and Variables

Declaring Variables:

#!/bin/bash
my_var="Hello, World"
echo $my_var  # Output: Hello, World

Command Substitution:

current_dir=$(pwd)
echo "Current directory: $current_dir"

2.2 File Management

Creating and Managing Files:

touch example.txt  # Create an empty file
echo "Some text" > example.txt  # Write to file
cat example.txt  # Display file content

Checking File Existence:

if [ -f example.txt ]; then
    echo "File exists"
else
    echo "File does not exist"
fi

2.3 Environment Variables and Permissions

Viewing and Modifying Environment Variables:

echo $HOME  # Display home directory
export MY_VAR="value"  # Set an environment variable
echo $MY_VAR

Changing Permissions:

chmod 775 script.sh  # Grant execute permission

2.4 Command-Line Arguments and Loops

Accessing Arguments:

echo "First argument: $1"
echo "All arguments: $@"

Loops:

for file in *.txt; do
    echo "File: $file"
done

2.5 Networking and System Monitoring

Ping Multiple Hosts:

hosts=("google.com" "example.com")
for host in "${hosts[@]}"; do
    ping -c 1 $host
done

Checking Active Ports:

netstat -tuln  # Display open ports

3. Python Scripting Basics

3.1 Essential Modules for Cybersecurity

  • os: File and directory operations.
  • socket: Networking.
  • subprocess: Command execution.
  • json & yaml: Configuration files.

3.2 Working with Files and Directories

List Files:

import os
print(os.listdir("."))

Read and Write Files:

with open("example.txt", "w") as f:
    f.write("Some text")

3.3 Network Operations with socket

Get Hostname and IP:

import socket
print(socket.gethostname(), socket.gethostbyname(socket.gethostname()))

3.4 Automating with subprocess

Run Commands:

import subprocess
result = subprocess.run(["ls", "-l"], capture_output=True, text=True)
print(result.stdout)

3.5 Handling JSON and YAML Configuration Files

JSON:

import json
config = {"user": "admin", "role": "cybersec"}
with open("config.json", "w") as f:
    json.dump(config, f, indent=4)

YAML:

import yaml
config = {"user": "admin", "role": "cybersec"}
with open("config.yaml", "w") as f:
    yaml.dump(config, f)

4. Intermediate Scripting Techniques

4.1 Error Handling and Validation

Python Example:

try:
    with open("nonexistent.txt", "r") as f:
        print(f.read())
except FileNotFoundError:
    print("File not found!")

Bash Example:

if ! [ -f example.txt ]; then
    echo "File not found!"
fi

4.2 Logging and Timestamping

Python Logging:

from datetime import datetime
now = datetime.now()
print(f"[{now}] Log entry")

Bash Logging:

echo "$(date): Log entry" >> log.txt

4.3 Argument Parsing

Python Argument Parser:

import argparse
parser = argparse.ArgumentParser()
parser.add_argument("filename")
args = parser.parse_args()
print(f"File: {args.filename}")

5. Advanced Scripting for Cybersecurity

5.1 Port Scanners

Python:

import socket
ip = "127.0.0.1"
for port in range(1, 1025):
    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
        if s.connect_ex((ip, port)) == 0:
            print(f"Port {port} is open")

5.2 File Integrity Checkers

Python:

import hashlib
with open("example.txt", "rb") as f:
    print(hashlib.sha256(f.read()).hexdigest())

5.3 Activity and Intrusion Detection

Log Suspicious Events:

with open("activity.log", "a") as f:
    f.write(f"[{datetime.now()}] Unauthorized access attempt\n")

6. Best Practices for Cybersecurity Scripts

6.1 Shebang and File Permissions

  • Use #!/usr/bin/env bash for Bash scripts and #!/usr/bin/env python3 for Python scripts.
  • Grant execute permissions with chmod +x.

6.2 Virtual Environments

Python:

python3 -m venv myenv
source myenv/bin/activate

6.3 Code Readability and Comments

Follow these guidelines:

  • Use meaningful variable names.
  • Comment critical logic.
  • Keep scripts modular and reusable.

7. Glossary

Symbol/Command Description
$ Access variables in Bash.
@ Represents all arguments in Bash.
* Wildcard for file matching.
socket (Python) Module for networking tasks.
subprocess (Python) Run shell commands in Python.

Sure! At the end of your guide, you can include a section linking to your repository:

8. Further Reference Examples

Explore a collection of scripting examples to reference on my GitHub repository:

GNAR1ZARD/Scripts

For a detailed guide on PowerShell and its scripting capabilities, please check out my guide here:
PowerShell Guide