Bash Basics

# Script ছাড়া: ২৫৪ বার এই command
ping -c 1 192.168.1.1
ping -c 1 192.168.1.2
# ...
ping -c 1 192.168.1.254
 
# Script দিয়ে: একটাই file চালাও
./ping_sweep.sh 192.168.1

# নতুন script file তৈরি করো
nano hello.sh

#!/bin/bash
 
echo "Hello, Omar!"
echo "আজকের তারিখ: $(date)"

# Script-কে executable করো
chmod +x hello.sh
 
# চালাও
./hello.sh
# Hello, Omar!
# আজকের তারিখ: Sat Apr 11 17:00:00 UTC 2026

#!/bin/bash

# bash কোথায় আছে দেখো
which bash
# /bin/bash

#!/bin/bash
 
# Variable তৈরি করো — = এর দুই পাশে space দেবে না
name="Omar"
target="10.10.10.50"
port=80
 
# Variable ব্যবহার করো — $ দিয়ে
echo "Name: $name"
echo "Target: $target:$port"

# Output:
# Name: Omar
# Target: 10.10.10.50:80

#!/bin/bash
 
# $(...) দিয়ে command-এর output ধরো
current_date=$(date)
my_ip=$(hostname -I | awk '{print $1}')
open_ports=$(ss -tlnp | grep LISTEN | wc -l)
 
echo "Date: $current_date"
echo "My IP: $my_ip"
echo "Open ports: $open_ports"

#!/bin/bash
 
echo "Target IP দাও:"
read target_ip
 
echo "Port দাও:"
read port
 
echo "Scanning $target_ip:$port..."
nc -zv $target_ip $port

# Prompt একই line-এ রাখতে
read -p "Target IP: " target_ip
read -p "Port: " port

#!/bin/bash
 
read -p "Port number দাও: " port
 
if [ $port -lt 1024 ]; then
  echo "Well-known port — system service"
elif [ $port -lt 49152 ]; then
  echo "Registered port — application"
else
  echo "Dynamic/Private port"
fi

#!/bin/bash
 
if [ -f "/etc/passwd" ]; then
  echo "File আছে"
fi
 
if [ -d "/tmp" ]; then
  echo "Directory আছে"
fi
 
if [ -x "/usr/bin/nmap" ]; then
  echo "nmap installed এবং executable"
fi

#!/bin/bash
 
# একটা list-এর প্রতিটা item
for user in root omar the-queen www-data; do
  echo "Checking user: $user"
done
 
# Number range
for i in {1..10}; do
  echo "Count: $i"
done
 
# IP range (ping sweep)
for ip in {1..254}; do
  ping -c 1 -W 1 192.168.1.$ip &>/dev/null && echo "192.168.1.$ip is alive"
done

#!/bin/bash
 
count=1
while [ $count -le 5 ]; do
  echo "Attempt $count"
  count=$((count + 1))
done

#!/bin/bash
 
# wordlist.txt-এর প্রতিটা word দিয়ে কিছু করো
while read -r word; do
  echo "Testing: $word"
done < wordlist.txt

#!/bin/bash
 
# $1 = প্রথম argument, $2 = দ্বিতীয়, $@ = সব
echo "Script নাম: $0"
echo "Target: $1"
echo "Port: $2"
echo "সব arguments: $@"
echo "মোট arguments: $#"

./script.sh 10.10.10.50 80
# Script নাম: ./script.sh
# Target: 10.10.10.50
# Port: 80

#!/bin/bash
 
if [ $# -eq 0 ]; then
  echo "Usage: $0 <target-ip>"
  exit 1
fi
 
target=$1
echo "Scanning $target..."

#!/bin/bash
 
# Color codes
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
NC='\033[0m'   # No Color — reset
 
echo -e "${GREEN}[+] Success${NC}"
echo -e "${RED}[-] Failed${NC}"
echo -e "${YELLOW}[*] Info${NC}"