Made Lua accept an argument, the path to a script to execute, and an option, -i, to enter interactive mode after executing that script, anyway.
Made process.load check for #!, running command instead of as Lua script directly. Let's see if things go horribly wrong, now.
Removed the config for the 'greeting' again, instead wrapped the functionality in a motd file that can be a script. Delete it to disable the greeting.