#!/bin/bash

# usage:
#  [[ $(host_reachable host.net) ]] && echo sure ||  echo nope
# or
# host_reachable &> /dev/null && echo sure || echo nope
# or
host_reachable () {
if [[ $(command -v nmap) ]] && [[ $2 ]]; then
 [[ $(nmap $1 -PN -p $2 | grep open) ]] && echo yes && return 0 || return 1
fi
if [[ $(command -v nc) ]] && [[ $2 ]]; then
[[ $(nc -w 2 $1 $2) ]] && echo yes && return 0 || return 1
fi
if [[ $(command -v ping) ]]; then
ping -c1 -W1 $1 &> /dev/null && echo yes && return 0 || return 1
fi
return 2  # return 2 to indicate no method was available
}

valid_ip()
{
    local  ip=$1
    local  stat=1
    local res

    if [[ $ip =~ ^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$ ]]; then
        OIFS=$IFS
        IFS='.'
        ip=($ip)
        IFS=$OIFS
        [[ ${ip[0]} -le 255 && ${ip[1]} -le 255 \
            && ${ip[2]} -le 255 && ${ip[3]} -le 255 ]]
          res=$([ $? == 0 ] && echo true || echo false)
      else
        res=false
    fi
    echo $res
}

get_domain() {
local domain
domain=$(echo $1 | awk -F\. '{print $(NF-1) FS $NF}')
echo "$domain"
}