Customize Vim's start screen.
This is a much simpler version of vim-startify.
By default it displays a random fortune(6), but this can be configured. Many
Linux systems don't ship with fortune(6) by default any more (shame on them!)
so you may get errors if you don't have it installed.
Set g:Startscreen_function to your prefered function to run on startup.
See :help startscreen for the full documentation.