First, you need to have a script that will run and backup everything you want backed up with no user input.
Then, use "cron" to schedule the script to run at the desired interval.
You could schedule a daily backup in either of the following ways:
1. use "crontab -e" to edit the cron schedule for "root", and insert a line something like this:
5 0 * * * /usr/local/hp/dpx/dpdaily >> /var/log/dpdaily.log 2>&1
(use "man 5 crontab" to get more info on crontab syntax)
2. Put a link to your unattended script (or just put the script itself) in the folder /etc/cron.daily
If your script generates any console output, it will be emailed to the local root account when the script is run. If you don't want this to happen, you have to redirect all script output, including error messages ("2>&1") to a log file.
There is also a "cron.weekly" folder, so you could make two scripts - one in "cron.weekly" that does an unattended full backup, and another in "cron.daily" that does an unattended incremental or differential backup.