Strange. It worked for me a few months ago. Maybe you need to do "sudo apt-get update" first?
Bitcoin Core works for bitcoind. You can also use Bitcoin ABC or Bitcoin Unlimited if you want to mine Bitcoin Cash.
Can I mine bitcoin case using a SHA256 ASIC? I haven't been mining in quite a long time. lol
The 'sudo apt-get update' did the trick. You might want to update your how-to info to include that so that others who aren't familiar with *nix can get ahead without having to ask the same question I did.

Thanks,