Files in the /etc/yum.d directory

  yum.cron.excludes
If there are certain rpm packages that you do not want to be updated with the
daily yum update.  By default the kernel is already in this file.  If you wish
to add more rpm packages, you need to list each one individually, all on the
same line, adding to those that are already there.
The contents in the yum.cron.excludes are added to the excludes line already in
your /etc/yum.conf.  If you do not have an excludes line there, then it will be added.

  yum.cron.primary & yum.cron.secondary
These files were removed.  The nightly yum cron uses whatever is in your /etc/yum.cron.

  original.yum.cron
This is the normal daily cron that is installed in /etc/cron.daily/

  checkonly.yum.cron
This can be substitued into the /etc/cron.daily/ directory for yum.cron if you
do not wish the daily yumming to actually install the rpm packages, but only
tell you if there are packages to be installed, and what they are.
Please be sure to edit the MAILLIST variable to send mail to who you expect to
send it to.

  byhand.yum.cron
This is a script that will interactivly run your yum.cron for you.  You have to
have had your yum.cron run before this can be run, because the yum.cron.byhand
uses the yum.conf files that the cron job creates.  
This is best used in conjunction with the yum.cron.checkonly.  You have
yum.cron.checkonly run each night, and if it tells you that there are updates
needed, you then run yum.cron.byhand
