Get last post from a static page

last_post.sh

#!/usr/bin/env sh

set -e
Url=$1

Sleep_Arg=$2
[ -z "$Sleep_Arg" ] && Sleep_Arg=60

get_http_header_last_modified () {
	curl "$1" --output /dev/null --silent --dump-header - \
		| grep Last-Modified 
}

notify_mail() {
	[ "$1" != "$2" ] \
		&& printf 'Page on address %s updated' "$3" \
		| mail -s 'Page updated' "$USER" 
}
while true; 
do
	Last_Modified_First="$(get_http_header_last_modified "$Url")";

	sleep $Sleep_Arg

	Last_Modified_Second="$(get_http_header_last_modified "$Url")";
	
	notify_mail "$Last_Modified_First" "$Last_Modified_Second" "$Url"
done