#!/bin/bash

# a simple script to check if a site has changed
# utilizes curl and sha1sum, so I guess these would be the dependiences
# information in the format [HH:MM:SS] <url> has changed
# is currently output to stdout, expect improvements here
# there is also minimal error checking, so it'll probably get fucked up
# with some exotic URLs or protocols or whatever
# XAVeRY 2009, public domain lol

if [ $# -ne 4 ] || [ $1 != "-u" ] || [ $3 != "-p" ]; then
	echo "Usage : $0 -u <url to check> -p <period in seconds>"
	exit
fi

newsum=""
oldsum=""

while [ TRUE ] ; do
	curl -s -o .tmpfile $2
	if [ $? -ne 0 ]; then
		echo 'curl execution returned an error, killing script...'
		exit
	fi
	nowasuma=`sha1sum .tmpfile | cut -b -40`
	if [ $nowasuma != $starasuma ]; then
		echo "[`date +%T`] $2 has changed!"
	fi
	starasuma=$nowasuma
	sleep $4
done