#!/bin/bash
awk -F'[\t ]+' '{
  if (!match($0, /^\s*(#|$)/)) {
    if (NF>=2 && length($2)) {
      host=$2
    } else {
      host=$1
    }
    if (!match(host, /^(localhost|local|localhost.localdomain|ip6-localnet|ip6-localhost$)$/)) {
      print "127.0.0.1 " host
    }
  }
}' adlists/* > block.list