I often find with CentOS that I find a reference to a package on the internet and it the pages says "this package is available in the repo", so then I do sudo yum install (as I know that I have that repo) and it comes up blank. I see this dozens of times (so much that if it says on an internet page "this is in the repo", I know that there is only a 50% chance of that being true.
Take a trivial example: fortune. Every page you will ever see says that it is in the EPEL repo. Ok, great yum install repo epel-release and then sudo yum install fortune. No such package exists!!!
I find here that the package seems to have been in CentOS 6 EPEL, but not after that. https://pkgs.org/download/fortune
So, in that case:
• How do I go about adding the CentOS 6 EPEL (and maybe also CentOS 7) repo to my CentOS 8 install?, and
• Tell my system to only use 7 if the package is not in 8 and to only use 6 if the package is not in 7?
• Also, is RPMforge still a valid repo? I saw a page saying that it was dead/deprecated, but do people still use that, and if so, how do I add it (maybe that helps me with many packages)?