README: add TOC

README.md

@@ -1,6 +1,40 @@
 # NixOS
 
-For each host (server, laptop, etc.), there is a subdirectory inside [hosts](hosts).
+- [NixOS](#nixos)
+  - [NixOS installation](#nixos-installation)
+  - [Update, build and switch](#update-build-and-switch)
+    - [Update](#update)
+    - [Build and switch: Using Colmena](#build-and-switch-using-colmena)
+    - [Build and switch: Manually](#build-and-switch-manually)
+      - [Option I: Build new config and activate it:](#option-i-build-new-config-and-activate-it)
+      - [Option II: Build new config and activate it during next boot:](#option-ii-build-new-config-and-activate-it-during-next-boot)
+      - [Option III: Build config and view changes:](#option-iii-build-config-and-view-changes)
+  - [niv: Dependency management](#niv-dependency-management)
+    - [Add Home Manager with niv](#add-home-manager-with-niv)
+    - [Add NUR with niv](#add-nur-with-niv)
+  - [disko and nixos-anywhere: Remote installation](#disko-and-nixos-anywhere-remote-installation)
+  - [Colmena: Deployment and secret management](#colmena-deployment-and-secret-management)
+  - [BTRFS swap file](#btrfs-swap-file)
+  - [LUKS Parameters](#luks-parameters)
+  - [Automount encrypted drive](#automount-encrypted-drive)
+  - [Failed services](#failed-services)
+  - [Garbage collection](#garbage-collection)
+  - [Run AppImages](#run-appimages)
+  - [General Notes](#general-notes)
+    - [Nix Pills](#nix-pills)
+    - [Papers](#papers)
+    - [System information](#system-information)
+    - [Search for packages](#search-for-packages)
+    - [Search for options](#search-for-options)
+    - [Search wich package owns a file](#search-wich-package-owns-a-file)
+    - [List files of package](#list-files-of-package)
+    - [Compare two versions of NixOS system profile](#compare-two-versions-of-nixos-system-profile)
+    - [NixOS configuration debugging](#nixos-configuration-debugging)
+    - [Show Nix configuration](#show-nix-configuration)
+    - [Evaluate NixOS configuration to JSON](#evaluate-nixos-configuration-to-json)
+    - [References](#references)
+  - [TODOs](#todos)
+
 
 ## NixOS installation
 
@@ -127,7 +161,7 @@ Add nixpkgs unstable:
 niv add NixOS/nixpkgs -n unstable -b nixpkgs-unstable
 ```
 
-## Add Home Manager with niv
+### Add Home Manager with niv
 
 Home Manager:
 
@@ -153,7 +187,7 @@ Use the corresponding branch:
 niv add nix-community/home-manager -n home-manager -b release-23.05
 ```
 
-## Add NUR with niv
+### Add NUR with niv
 
 > The Nix User Repository (NUR) is community-driven meta repository for Nix packages.
 > 
@@ -244,7 +278,7 @@ sudo nixos-generate-config --dir hosts/$(hostname)
 
 * If it is an SSD, enable `boot.initrd.luks.devices.<name>.allowDiscards`
 
-### Failed services
+## Failed services
 
 If there are e.g. file conflicts due to preexisting dotfiles, the Home Manager user service might fail. To list all failed services, run: