Bash Scripting Basics

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Course URLs:

  1. Advanced Bash Scripting
  2. Ethical Hacking with Bash
  3. Cybersecurity Automation

You Should Know:

Bash scripting is essential for automating tasks in cybersecurity, system administration, and penetration testing. Below are key concepts, commands, and practical examples to master Bash scripting.

1. Basic Bash Script Structure

A Bash script starts with a shebang (!/bin/bash) to specify the interpreter.

!/bin/bash 
echo "Hello, Cybersecurity World!"

2. Variables and User Input

!/bin/bash 
read -p "Enter your name: " username 
echo "Welcome, $username!"

3. Conditional Statements

if [ "$1" == "hack" ]; then 
echo "Starting penetration testing..." 
else 
echo "Invalid command." 
fi

4. Loops for Automation

For Loop:

for ip in {1..10}; do 
ping -c 1 192.168.1.$ip 
done

While Loop:

counter=1 
while [ $counter -le 5 ]; do 
echo "Count: $counter" 
((counter++)) 
done

5. Functions for Reusable Code

function scan_ports() { 
nmap -p 1-100 $1 
} 
scan_ports "example.com"

6. File Operations

 Read a file line by line 
while IFS= read -r line; do 
echo "$line" 
done < "file.txt"

7. Command-Line Arguments

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

8. Error Handling

if ! command -v nmap &> /dev/null; then 
echo "Nmap not found. Installing..." 
sudo apt install nmap -y 
fi

9. Scheduling with Cron

Add a script to run daily:

(crontab -l 2>/dev/null; echo "0 3    /path/to/script.sh") | crontab -

10. Network & Security Scripts

Check Open Ports:

nc -zv target.com 80 443 22

SSH Bruteforce Protection:

sudo fail2ban-client set sshd banip 192.168.1.100

What Undercode Say

Bash scripting is a must-have skill for cybersecurity professionals. It enables automation, log analysis, and penetration testing tasks. Mastering loops, conditionals, and system commands (grep, awk, sed) will enhance efficiency.

Key Linux Commands for Cybersecurity:

– `chmod +x script.sh` (Make script executable)
– `sudo tcpdump -i eth0` (Packet sniffing)
– `find / -perm -4000` (Find SUID files)
– `history | grep “ssh”` (Audit past commands)
– `openssl aes-256-cbc -in file.txt -out file.enc` (File encryption)

Windows Equivalent Commands:

– `netstat -ano` (Check open ports)
– `schtasks /create` (Schedule tasks)
– `whoami /priv` (Check user privileges)

Prediction

As automation grows, Bash scripting will remain critical in cybersecurity for rapid vulnerability scanning, log analysis, and incident response. Future trends may integrate AI-driven Bash scripts for threat detection.

Expected Output:

A fully functional Bash script tailored for cybersecurity tasks, integrating loops, conditionals, and system commands for automation.

References:

Reported By: Zlatanh Bash – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅

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