keytool.
However, that's just for
Java certs. If you want to install a cert for Apache, you have to edit the Apache configuration. There's also a directory in the /etc designed to hold the actual cert files, although I don't remember its exact name (which varies, depending on the RHEL version).
The secret of how to be miserable is to constantly expect things are going to happen the way that they are "supposed" to happen.
You can have faith, which carries the understanding that you may be disappointed. Then there's being a willfully-blind idiot, which virtually guarantees it.