Tracking changes to a website

Tracking changes to a website is helpful to web developers and users. Checking a website manually in intervals is really hard and impractical. Hence, we can write a change tracker running at repeated intervals. When a change occurs, it can play an audio or send some other notification. Let us see how to write a basic tracker for the website changes.

Getting ready

Tracking changes in terms of Bash scripting means fetching websites at different times and taking the difference by using the diff command. We can use curl and diff to do this.

How to do it...

Let's write a Bash script by combining different commands, to track changes in a web page:

#!/bin/bash
#Filename: change_track.sh
#Desc: Script to track changes to webpage

if [ $# -ne 1 ];
then 
  echo -e "$Usage: $0 URL\n"
  exit 1;
fi

first_time=0
# Not first time

if [ ! -e "last.html" ];
then
  first_time=1
  # Set it is first time run
fi

curl --silent $1 -o recent.html

if [ $first_time -ne 1 ];
then
  changes...