This is very simple but must be done from the root user. Please keep in mind that there is not always a repository version for your version of CentOS.
Step 1:
Log into your servers command line.
Step 2:
Run the following command to download any updates from your current repositories.
yum -y update
Step 3:
Generally it is a good practice to run the following to clear any cached data regarding the installed packages as this can take up a lot of disk space.
yum clean all
