Good luck on your certification journey. Unlike some of my other multichoice certifications I really felt some sense of accomplishment getting my RH certifications.
Like you, during my RHCSA and RHCE studies I was very overwhelmed with the amount of things you need to know in the CLI to get anywhere.
My biggest advice (and what I found for myself) is to check the requirements of the course and know how to use the man pages.
Example objective from the EX200 is "Configure firewall settings using firewall-cmd/firewalld".
What you want to know is the following:
- Generic basic networking (TCP/IP, ports, application and port associations).
- What a firewall is in general and vaguely how it works.
- The general command (firewall-cmd).
With that in mind, the big secret is to then man firewall-cmd and go to the EXAMPLES section where it explicitly lays out example commands how to do some basic stuff.
About half the things I got in my exams I knew how to do with experience and the other half I figured out quickly using the examples in the man pages. If you rely heavily on the man pages, you run the risk of running out of time; so a balanced approach may be ideal.
Just watch out for the things you may not be able to do because you cannot yet reach operating level for man pages. Basic sysadmin tasks like like recovery kernel or booting broken by SELinux/resetting root password (what ever low level administrator type stuff in the objectives).
Hope this helps.
