Tool to update DNS at freedns.afraid.org using curl&dig [v.2.0]

dnsupdate.sh

#!/bin/bash

HLPARG=--help
KDEARG=--kde
HOSTSARG=--hosts
DOM=$1
HASH=$2
HOSTS=/etc/hosts

if [ -n "`echo $@ | grep -o -- $HLPARG`" ]

then
  OUT="Tool to update DNS at freedns.afraid.org.\n\n\
Usage: dnsupdate.sh [DOMAIN] [UPDATE HASH] [OPTION]\n\n\
Options:\n\t--help\t\tprint this help.\n\
\t--hosts\t\tmodify domen entry in /etc/hosts, the entry must exist.\n\
\t--kde\t\toutput to KDE system notifications.\n\n\
Originally written by Adam Dean.\n\
See it at http://freedns.afraid.org/scripts/update.sh.txt\n\
Mail bug reports and suggestions to <dap.darkness at gmail dot com>."

else
  IPREG="`dig @8.8.8.8 $DOM | egrep -v "^$|;" | awk '{ print $5 }'`"

  IPCUR="`curl -s http://checkip.dyndns.org | grep -o '[0-9.]*'`"

  if [ "$IPCUR" != "$IPREG" ]

  then
    OUT="`curl -s "http://freedns.afraid.org/dynamic/update.php?"$HASH`"

    if [ -n "`echo $@ | grep -o -- $HOSTSARG`" ]

    then
      cp $HOSTS $HOSTS.bak

      sed "s/`grep $DOM $HOSTS | awk '{ print $1 }'`/$IPCUR/g" $HOSTS.bak > $HOSTS
    fi

  else
    OUT="Address "$IPCUR" has not changed." 
  fi
fi

if [ -n "`echo $@ | grep -o -- $KDEARG`" ]

then
  kdialog --title "DNS update" --passivepopup "$OUT"

else
  echo -e "DNS update:\n""$OUT"
fi