#!/bin/bash
#=================================================================
# Speedy Nmap
#=================================================================
# Performs nmap scan in hyper speed.
# Usage: ./speedy_nmap.sh <IP> <output file>
#
# Author: PotatoMaster101
# Date:   22/10/2018
# File:   speedy_nmap.sh
#=================================================================


#-----------------------------------------------------------------
# main
#-----------------------------------------------------------------
# Starts the scanning process.
#
# PARAMS:
# $1 - the IP to scan
# $2 - the output file name
#-----------------------------------------------------------------
function main {
    if [[ $# -ne 2 ]]; then
        echo "usage ./speedy_nmap.sh <IP> <output file>"
        return 1
    fi
    rm -f $2

    # start scanning
    limit=4369
    for i in {1..15}; do
        lower=$((limit - 4368))
        echo "scanning $lower to $limit..."
        nmap_range $lower $limit $1 $2 &
        limit=$((limit + 4369))
    done
    wait
    echo "scan done"
}


#-----------------------------------------------------------------
# nmap_range
#-----------------------------------------------------------------
# Scans the specified port range using nmap.
#
# PARAMS:
# $1 - the lower bound
# $2 - the upper bound
# $3 - the IP to scan
# $4 - the output file name
#-----------------------------------------------------------------
function nmap_range {
    nmap "-p$1-$2" -T5 -Pn -n -sS -sV $3 > $1

    # write to file if output contains any open port
    grep -q All $1
    if [[ $? -ne 0 ]]; then
        cat $1 >> $4
    fi
    rm -f $1
}


main $@
exit $?