How can I automatically copy files from a source directory to the destination directory after some time say like after every 30 minutes?
If your using a standerd LAMP stack you could just make a cron job that calls rsync.
eg run crontab -e
and add an entry such as
* * * * * rsync -av /path/to/files/source/ /path/to/copy/files/to/
will copy the files ever 1 min.
check out:
http://en.wikipedia.org/wiki/Cron
and
http://en.wikipedia.org/wiki/Rsync