Have you ever found yourself in a situation, when you forgot what you did to your OS a few years ago and wondering how to repeat this configuration/fix on the new installation? Ever wanted to manage your Operating System as a simple programming project, just a repository with the source code of a declarative description of your whole OS and its components? It's quite possible with GNU Guix functional package manager and rde distribution on top of it.

The whole GNU Linux OS built from a Lisp (Scheme) source: no need for any manual actions, no more half-working config files or hacky bash scripts, just write the code in a general puprpose functional programming language and get your complete and always working Operating System for free :) If something doesn't work as you expect, rollback with CLI or pick a previous generation from a bootloader menu. If you forgot what change you've made, check out the source code or version control system's log. Want to deploy the OS over SSH to remote host? Want deploy it to the cluster using containers instead of real hardware? - it's all doable.

This is already huge, but it's only a fraction of what is possible when you program OS distribution with a good functional programming language.