A website change checker / detection changer / script to keep track of changes of any website (URL). Intended to be run on a 24/7 running server like a login server in your university institute.

website-notify.sh

#!/bin/bash
#
# Notify when website changes-script:
#   This is a simple mini program that informs you whenever a website
#   changes. Can perform any job when triggered.
# Usage:
#   ./notify "jobname fuer mail" "http://abc.def/interessant.html"
# The script will run "in foregrund". You can e.g. use GNU screen to detach it
# and run it in the background on a 24h-running-server:
#   $ screen
#   $ ./notify ...
#     => now press CRTL (STRG in german) + a + d <=
#   [detached from 2850.pts-0.phoebe]
#   $
#     => if you want your screen session back: <=
#   $ screen -r
#     => same CRTL + a + d as above <=
#   read `man screen` for further instructions.
#
# Written just for fun by Sven, 2011
# (Actually written to be notified when exam grades are online)
# Public Domain


job="$1"
url="$2"
additional_mailto="$3"
mailto="my-email-adress@example.com"
delay=5m
notify_delays=876

new_file=`mktemp`
old_file=`mktemp`
dealys_elapsed=0

get() {
	wget -qO$1 $url
}

final_sendmail() {
	mailto="$mailto $additional_mailto"
	sendmail "$1" "$2" "$3"
}

sendmail() {
	# usage: sendmail "title" "text" [file to attach]
	text=`mktemp`
	cat > $text << EOF
Website notify script auf $(hostname) um $(date -R).
Jobname: $job
Beobachtete URL: $url

Nachricht: $2

EOF
	[[ $3 ]] && cat $3 >> $text
	cat $text | mail -s "$job Website notify - $1" $mailto
	rm $text
}

# initial
get $old_file
echo "Type 'rm $old_file' to stop this program checking for updates"

while [ -f $old_file ];
	do get $new_file;
	diffout=$(mktemp)
	diff $old_file $new_file > $diffout
	if [ $? != 0 ]; then
		echo "URL content changed!"
		# play a sound: mpg123 /your/music.mp3
		# popup a window: xmessage "$job was updated"
		# nicer window:
		# zenity --info --text="$job was updated"
		# send a mail:
		final_sendmail "AKTUALISIERT" "Website wurde aktualisiert!" $diffout
	else
		delays_elapsed=$[ $delays_elapsed + 1 ]
		if [[ $delays_elapsed == $notify_delays ]]; then
			# notify that I'm still living
			echo Notify living
			sendmail "notify" "Program waiting ($delay x $notify_delays)"
			delays_elapsed=0
		fi
	fi
	rm $diffout
	mv $new_file $old_file
	sleep $delay
done;

echo "program quit since $old_file was deleted"
exit 1