pagewatcher.sh - MySimplePageWatcher - Watch a webpage for changes

pagewatcher.sh

#!/bin/bash

# Page watcher Cronscript
# initial 201804xx

if [ $# -lt 1 ] ; then
 echo "pagewatcher watches an url and sends an e-mail in case of changes."
 echo
 echo "usage: pagewatcher.sh url [additional-mail-recipients] | clean"
 echo
 exit
fi

if [ $1 = "clean" ]; then
	rm /tmp/pagewatch-*
	exit
fi

url=$1
sendmailonfirstrun="false"

mailto="root"
if [ "$2" != "" ]; then
	mailto="root,$2"
fi

md5=$(echo -n "$url" | md5sum | awk '{ print $1 }')
page="/tmp/pagewatch-${md5}"
pagelast="${page}.last"
diff="${page}.diff"

mail="/usr/bin/mail"

wget $url -O "${page}" &> /dev/null

if [ ! -f "${pagelast}" ]; then

	if [ $sendmailonfirstrun = "true" ]; then
		touch "${pagelast}"
	else
		cp "${page}" "${pagelast}"
	fi

fi

if [ -s "${page}" ]; then

   # Are there differences to the last run?
   diff -q "${pagelast}" "${page}" > /dev/null 2>&1

   if [ $? -ne 0 ] ; then

	echo -e "$url has changed.\n" > "${diff}"
	diff --suppress-common-lines -u0 "${pagelast}" "${page}" >> "${diff}" 2>&1
	$mail -s "$url has changed." $mailto < "${diff}"
	
	cp "${page}" "${pagelast}"
	rm "${diff}"

   fi
fi