Bash - Bourne Again Shell

#!/bin/bash
# This is a comment

# Variables
TARGET="192.168.1.1"
PORT=443

# Echo with quotes (preserve spacing)
echo "Scanning $TARGET on port $PORT"

# Command substitution
CURRENT_USER=$(whoami)
IP_ADDR=$(hostname -I | awk '{print $1}')

# If/else
if [ "$1" == "" ]; then
    echo "Usage: $0 <target>"
    exit 1
fi

# If with command result
if ping -c 1 192.168.1.1 &>/dev/null; then
    echo "Host is up"
else
    echo "Host is down"
fi

# For loop
for ip in 192.168.1.{1..254}; do
    ping -c 1 -W 1 $ip &>/dev/null && echo "$ip is up"
done

# While loop
while read line; do
    echo "Processing: $line"
done < input.txt

scan_port() {
    local host=$1
    local port=$2
    timeout 1 bash -c "echo >/dev/tcp/$host/$port" 2>/dev/null && echo "$port open"
}

# Quick port scanner in pure bash
for port in 22 80 443 3389 8080; do
    scan_port 192.168.1.1 $port
done

# Check if file exists
[ -f /etc/passwd ] && echo "File exists"

# Check if directory exists
[ -d /tmp/loot ] || mkdir -p /tmp/loot

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

# Append to file
echo "result" >> output.txt

# Write file
cat > /tmp/script.sh << 'EOF'
#!/bin/bash
whoami
EOF

# Ping sweep
for i in {1..254}; do ping -c1 -W1 192.168.1.$i &>/dev/null && echo "192.168.1.$i up" & done; wait

# Port scan
for p in {1..1024}; do timeout 0.5 bash -c "echo >/dev/tcp/192.168.1.1/$p" 2>/dev/null && echo "$p open"; done

# Extract IPs from file
grep -oP '\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}' file.txt | sort -u

# Watch a log file for specific string
tail -f /var/log/auth.log | grep --line-buffered "Failed"

# Kill process by name
pkill -f "airmon-ng"

# Run command on multiple hosts
for host in 10.0.0.{1..10}; do ssh $host "uname -a"; done

#!/bin/bash

while [[ $# -gt 0 ]]; do
    case $1 in
        -t|--target)
            TARGET="$2"
            shift 2
            ;;
        -p|--port)
            PORT="$2"
            shift 2
            ;;
        -h|--help)
            echo "Usage: $0 -t TARGET -p PORT"
            exit 0
            ;;
        *)
            echo "Unknown option: $1"
            exit 1
            ;;
    esac
done