Send email and tweet when a web page changes in bash.

monitor-page.sh

#!/bin/bash
# inspired in "Monitoring a web page for changes using bash"
# http://bhfsteve.blogspot.com.es/2013/03/monitoring-web-page-for-changes-using.html
# monitor.sh - Monitors a web page for changes
# sends an email notification and a tweet if the file changes

# requirements: 
# - twitter from the command line [https://github.com/sferik/t]
# gem install t
# - sendemail 
# sudo apt-get install libio-socket-ssl-perl libcrypt-ssleay-perl libnet-ssleay-perl
# sudo apt-get sendemail

URL="http://example.com/monitored/page.html"
TO="email@example.com another@example.com"
HANDLER="@user @friend"

USERNAME="sender@gmail.com"
PASSWORD="secret!"


while true ; do
    if [ -f new.html ] ; then
        mv new.html old.html 2> /dev/null
    fi
    curl -s $URL -L --compressed > new.html
    # for better results add a grep to exclude lines that always change (like a date, etc.)
    #  | egrep -v 'this|that'
    DIFF_OUTPUT=`diff  --suppress-common-lines -y new.html old.html`
    if [ "x" != "x${DIFF_OUTPUT}" ] ; then
        t update "${HANDLER} hey, the webpage $URL just changed"
        sendEmail \
            -t $TO \
            -f $USERNAME \
            -s smtp.gmail.com:587 -xu $USERNAME -xp $PASSWORD \
            -o tls=yes \
            -u "The page changed" \
            -m "Visit it at $URL\n\n${DIFF_OUTPUT}"
    fi
    sleep 300
done