Because I will have to do this again in no time, here I jot down the quickest way for me to install 12c. This is the usual series of following steps, running into an error, searching for a fix, lather, rinse repeat.
Step One – Install oracle-rdbms-server-12cR1-preinstall.
Step Two – …gets us all the way here – [FATAL] PRVF-0002 : Could not retrieve local nodename
Step Three – … cannot write oradata change to /home/oracle/oradata
Step Four – Swapfile … I used 10000
Step Five – Then I see installer is bent on putting oradata directory in /home. Just revise to suit your install.