:date: 2014-04-20 19:27

.. index:: tech, scripting, monitoring

.. _`monitoring`:

Monitoring
==========
Sometimes you just want to see if a webpage changed. A simple one. No RSS available and you know that writing to the one running it and asking for RSS would go probably beyond his/her capacities. Sometimes it doesn't even make sense.

So what to do?

This little script in Cron will now check a website and send me a mail when it detects a change. It isn't pretty, but it works.

.. code:: bash

   #!/bin/bash
   # Checking for changes of a webpage
   USERNAME="emailuser"
   PASSWORD="emailpw"
   URL="http://URL/I/WANT/TO/CHECK"
   
   #for (( ; ; )); do
       mv new.html old.html 2> /dev/null
       curl $URL -L --compressed -s > new.html
       DIFF_OUTPUT="$(diff new.html old.html)"
       if [ "0" != "${#DIFF_OUTPUT}" ]; then
           sendEmail -f $USERNAME -s smtp.example.com:25 \
               -xu $USERNAME -xp $PASSWORD -t $USERNAME \
               -o tls=yes -u "Web page changed" \
               -m "Visit it at $URL"
   	# sleep 10
       fi
   #done

The commented lines will run the script in a loop with a pause of 10 seconds. I don't need an email right away, so I put the script in cron instead.