how to update the security patch for linux OS.
 

Hi, windows system OS, we can update the security patch from windows update website or download a *.exe file to update to windows system. RHEL5(redhat) if have subscribe to redhat than how to update the security patch like windows, or if not subscribe than how to update.Centos how to update the security patch.
Thank you.

In RHEL/CentOS you do not get "security patches" on patch Tuesday like with Windows. Instead, patches are called "updates" and you are offered them as soon as they are ready - often the same day as the fix. There are also many more of them a month, and they are smaller.

Some updates will be called "security updates", and they will have their own repositories online.

A solo fat client will have updates managed by up2date (RHEL) or YUM (CentOS) which will be configured to check the repositories regularly (usually daily) for a list of available updates. This is the default action - and needs an internet connection. The user is notified by an icon in the toolbar when an update is available.

In a production environment, it is usual to set one machine as a local repository and have all the computers on the network get their security updates from that - usually automatically.

I THINK as of RHEL5, RH uses yum as well. RHEL4 CAN be set up to use yum with Centos repos as a source. If the auto check has been shut off (many would consider this a good idea, including me) one can (as root);

The first will give you a list of the packages purposed for updates and the second will update.

From the RHEL5 Release Notes:
... good heads-up there lazlow