MySQL_WPB is small and simple bash script with task to backup almost any web project developed with MySql. I have developed it for backuping joomla projects but it can be adjusted to backup almost any project which use MySQL. This script requires you to have tar, bzip and mutt (optionally) installed on your system. And usually it is run as cron job. This script dumps database to a file and save it to joomla (or any other) directory. Then it tar and compress (bzip2) that hole directory and saves this compressed file to some other directory (or in the same directory). That means all joomla installation with all media files, joomla extensions and language files will be backuped. Optionally it can send backup file by email and after that delete local copy.
Version 2 has ability to check are there some changes happened after last backup. If there are it will backup if there are no change it will stop backup process.