I would like to install Cabal on my POWER8 RHEL 7.9 system.
curl --proto '=https' --tlsv1.2 -sSf https://get-ghcup.haskell.org | sh
Upon running this I answered all the questions with the default answer and then it said:-
Unknown architecture: ppc64le
So, how do I install haskell, and thus cabal on my system?
PowerPC is a Tier 2 platform for GHC (See https://gitlab.haskell.org/ghc/ghc/-/wikis/platforms). That means that it probably works, but it is not supported by the core development team.
https://www.haskell.org/ghc/distribution_packages has details of where you can get various of the tier 2 platforms from, and specifically for ppc64le which you are after, there is a section titled, "Fedora and EPEL" which suggests you can install it thus:-
dnf install ghc.
Of course, first you'll have to install
dnf which is in the EPEL.
Failing that you'll probably have to compile GHC from source. You can try following the instructions here: https://gitlab.haskell.org/ghc/ghc/-/wikis/building/hadrian, but that is going to take some effort.