问是否有任何linux shell代码来监控网页的相对于html标签的更改？

EN

#!/bin/sh
# monitor.sh - Monitors a web page for changes
# sends an email notification if the file change

URL="http://rads.stackoverflow.com/amzn/click/B0029WGLOQ"

for (( ; ; )); do
    curl $URL -L --compressed -s > data.html
    grep '<span id=\"priceblock_ourprice\"' data.html > price_tag_dump_new.tsv
    if [[ -s $price_tag_dump_new.tsv ]] ; then
      echo "No Change"
    else
      echo "URL data on $URL has changed" > change_log.tsv
    fi
    rm price_tag_dump_old.tsv data.html
    mv price_tag_dump_new.tsv price_tag_dump_old.tsv
    sleep 10
done