Bash Scripting Tutorial – Linux Shell Script and Command Line for nmap automate

 Ever wondered how Linux professionals automate tasks so effortlessly?

The secret lies in Bash scripting — one of the most powerful skills you can learn as a beginner in Linux.

💡 What you’ll learn in this tutorial:
✔️ Basics of Linux command line
✔️ How to create and run your first shell script
✔️ Understanding variables, loops, and conditions
✔️ Automating daily repetitive tasks
✔️ Real-world examples to build confidence

🧠 Why Bash scripting?
Because it transforms you from someone who uses commands…
into someone who controls the system.

Whether you're stepping into IT, cybersecurity, or DevOps — this is your foundation.

⚡ No heavy theory. No confusion.
Just clear, practical learning for beginners.

👉 Start now and take your first step toward mastering Linux.

🛠️ Automated Nmap Scan Script (Beginner → Practical)

This is the command , for bash script .

It require the scan type

Final result will be on the same drive.

Now the script is below .

#!/bin/bash

# ==============================

# Nmap Automation Script

# ==============================

# Create output directory with timestamp

timestamp=$(date +"%Y-%m-%d_%H-%M-%S")

output_dir="nmap_scan_$timestamp"

mkdir -p "$output_dir"

echo "=============================="

echo " Nmap Automation Script Start "

echo "=============================="

# Ask user for target

echo "Enter target IP or subnet (e.g. 192.168.1.1 or 192.168.1.0/24):"

read target

# Ask scan type

echo "Select Scan Type:"

echo "1) Quick Scan"

echo "2) Full Port Scan"

echo "3) Stealth Scan"

read choice

# Define scan based on user choice

case $choice in

    1)

        scan_type="-T4 -F"

        scan_name="quick_scan"

        ;;

    2)

        scan_type="-p- -T4"

        scan_name="full_scan"

        ;;

    3)

        scan_type="-sS -T4"

        scan_name="stealth_scan"

        ;;

    *)

        echo "Invalid choice. Exiting..."

        exit 1

        ;;

esac

# Run Nmap scan

echo "Running Nmap scan on $target ..."

nmap $scan_type $target -oN "$output_dir/${scan_name}.txt" \

                       -oX "$output_dir/${scan_name}.xml" \

                       -oG "$output_dir/${scan_name}.gnmap"

# Check if scan was successful

if [ $? -eq 0 ]; then

    echo "Scan completed successfully!"

else

    echo "Scan failed!"

    exit 1

fi

# Extract open ports

echo "Extracting open ports..."

grep "open" "$output_dir/${scan_name}.gnmap" > "$output_dir/open_ports.txt"

# Summary

echo "=============================="

echo " Scan Completed "

echo "Results saved in: $output_dir"

echo "Open ports saved in: open_ports.txt"

echo "=============================="

▶️ How to Use

chmod +x nmap_auto.sh
./nmap_auto.sh

🧠 What This Script Actually Does (Important)
This is not just a script — it mimics real-world security workflow:
✔️ Creates timestamped scan folders
→ Like SOC evidence storage
✔️ Supports multiple scan types
→ Quick / Full / Stealth
✔️ Saves output in 3 formats


.txt → human readable


.xml → for tools (ELK/Splunk integration)


.gnmap → grep-friendly


✔️ Extracts open ports automatically
→ Useful for alerting & correlation