How do i check redhat linux for software security updates?

[saolasosme]

Using the yum command with the option:

       check-update
              Implemented  so  you  could know if your machine had any updates
              that needed to be  applied  without  running  it  interactively.
              Returns exit value of 100 if there are packages available for an
              update. Also returns a list of the packages  to  be  updated  in
              list  format. Returns 0 if no packages are available for update.
              Returns 1 if an error occurred.  Running in  verbose  mode  also
              shows obsoletes.

The command provides a summary at the end.

$ sudo yum check-update --security
...
...
...
No packages needed for security; 86 packages available