First of all, in any large company, you work as part of what may be a rather large
team, and it is comparatively rare for you to be asked to set up an entirely new system configuration. Most of the time, that's already been done. (And probably saved as a snapshot or a VM-template so that the process of setting up a new machine is "just add water.")
I suggest that you spend time with Linux (on a VM ...) to become familiar with how to set it up, mess things up and then fix them,
without using a GUI to do everything. (Most production machines do not have a GUI.)
I suggest that you not limit yourself to "Red Hat." Set up several VMs with several different versions of Linux on it – particularly Ubuntu LTS.
And then – look for an entry-level job. Be completely up-front with the interviewer about what you do and don't know, and how you learned what you know now. Emphasize that you are a
team player, not a "lone wolf," and that you will faithfully(!)
be there when the going gets tough. That you will be
reliable and very, very attentive to detail.
If someone wants you to have "a certification," then
they should send you to classes and pay for those classes out of their employee continuing-education budget. They more-likely have internal training programs in place for new hires, because every "shop" is unique and different. Although certification programs are
one way to train employees, they have also been criticized for being too generic and for lack of quality-control over the instruction delivery process. If your employer uses certifications, then they have also vetted their one approved vendor, or they bring the training in-house.
If you encounter a company that expects you to have a certification – i.e. "on your own nickel" – as a pre-requisite for employment, I would simply move on to your next prospect, instead.
P.S.: I
do pick up certification-training books at a used book store and flip through them. Although they are usually far too vendor-specific and vendor-version specific for my use, you might find in them some suggestions concerning problem-scenarios and diagnostic techniques. But it might be more productive to read a lot of
man pages.
"How does CUPS actually work?", for instance. (That is to say, "when
it does ...") Do online searches where people discuss the problems that they've been having lately, and read the answers where people try to help fix them.
Also, read this site –
LQ –
every day, as I do.