#!/usr/bin/sh
# 2000.07.31 David Fischer <fischer_dj@mailcity.com>
#
# This script is meant to be called periodically by the cron function but can
# be run from the command line. Note, it currently automatically updates 
# the crontab file. If you already use the crontab file, you need to modify
# this script or your current crontab settings will be lost!
#
# The arguments for DNWatcher tell it the current day of the year, the number of 
# days between "Still Alive" messages, the notification email address, and then
# the domain names to watch. When called, it checks each of the domain names via "whois".
# If the "whois" output contains "No match", a message stating that domain name is available 
# is emailed to the notification address. If the given number of days have passed since
# the current date, a "Still alive" message is emailed, as a reminder, stating which
# domain names are being monitored. Finally, it updates the crontab file with the current
# day, and exits.
#
# Use the crontab to run this automatically with 
# desired Domain names as arguments
# setenv EDITOR emacs
# crontab -e
# (don't enter this...)                                   <day  email   domain names...>
# (enter this sort of thing) 5 0,6,12,18,21 * * * dnwatcher 0 1 fischer fischer.com fischer.net 
# (...or this)                                               days between "still alive" emails
# The above runs it 5 minutes past midnight, 6am, noon, 6pm, and 9pm
# every day, every month, checking the availability of 
# fischer.com fischer.net. Every day, it send an email to fischer, 
# telling what domain names are being watched. Note, this will write over
# your crontab file contents. If you use your crontab currently, you will
# need to modify this script. (If you do, please send me the changes)
#
# Save this script with the name "dnwatcher" and place it in your home directory
# Make it file executable by executing the command:
# chmod a+x dnwatcher
#

PATH=/usr/local/script:/usr/local/bin:/usr/optics/script:/usr/optics/bin:/usr/hosts:./bin:.:/usr/ceas/lang/SC2.0.1:/usr/optics/insite/bin:/usr/openwin/bin:/usr/openwin/demo:/usr/ceas/script:/usr/ceas/bin:/usr/ceas/bin/X11:/usr/ucb:/home/moe/fischer/bin:/bin:/usr/bin:/usr/demo:/usr/games:/usr/new:/etc:/usr/etc:.:/usr/ceas/lib:/usr/ceas/cap:/usr/ucb:/usr/lib; export PATH

arglen=`echo "$*" | wc -c | cut -c1-8`
arglen=`expr $arglen - 1`

day_prev=$1
day_skip=$2
addy=$3
day_now=`date +%j`
day_diff=`expr $day_now - $day_prev`
day_mod=`expr $day_diff % $day_skip`

shift
shift
shift

if [ $day_mod -eq 0 -a $day_diff -ne 0 ]; then #if right number of days has passed

(
cat <<!
Subject: DN Watcher still alive
The domain name watcher is watching:
$*
!
) | sendmail $addy

(
cat <<!
5 0,6,12,18,21 * * * dnwatcher $day_now $day_skip $addy $*
!
) | crontab

fi


while [ "$#" -ge 1 ]; do

if [ `(whois $1 | egrep -ci 'No match')` -ge 1 ]; then

(
cat <<EOF
Subject: "$1" available!
Domain Name "$1" is now available!
EOF
) | sendmail $addy

fi
shift

done

exit 0