YUM cron for automatic security updates.

yum-security.cron

#!/bin/sh
yum -y -R 120 -d 0 -e 0 update yum
yum --security -y -R 10 -e 0 -d 0 update

-R, --randomwait=[time in minutes]
              Sets the maximum amount of time yum will wait before
              performing a command - it randomizes over the time.
-d, --debuglevel=[number]
              Sets the debugging level to [number] - turns up or down the
              amount of things that are printed. Practical range: 0 - 10
              Configuration Option: debuglevel
-e, --errorlevel=[number]
              Sets the error level to [number] Practical range 0 - 10. 0
              means print only critical errors about which you must be told.
              1 means print all errors, even ones that are not overly
              important. 1+ means print more errors (if any) -e 0 is good
              for cron jobs.
              Configuration Option: errorlevel
-y, --assumeyes
              Assume yes; assume that the answer to any question which would
              be asked is yes.
              Configuration Option: assumeyes