diff --git a/notebook/lang.nix.org b/notebook/lang.nix.org
index 3a3ff0d..be4c5d8 100644
--- a/notebook/lang.nix.org
+++ b/notebook/lang.nix.org
@@ -3,7 +3,7 @@
 :END:
 #+title: Nix language
 #+date: "2021-06-30 13:30:19 +08:00"
-#+date_modified: "2021-07-19 11:30:52 +08:00"
+#+date_modified: "2021-12-28 00:17:58 +08:00"
 #+language: en
 
 
@@ -18,18 +18,24 @@ This is just a personal reference note, the recommended resource for learning th
 
 * What is it for?
 
-- most importantly, writing packages
+- most importantly, writing packages, specifically [[id:8f23f862-a19a-4a13-8d8f-69c280a8e072][Nix derivations]]
 - mostly used for configuring [[https://nixos.org/manual/nixos/stable/][operating systems]] and create servers quickly with its variety of services
 - configuring [[id:3b3fdcbf-eb40-4c89-81f3-9d937a0be53c][Nix package manager]]
 
 
 
 
-* Derivations
+* Builtins
+
+- ~builtins.toString ./.~ will print out the current directory.
+- ~builtins.getFlake $PATH~
+
+
+** Imports
+
+- the =import= builtin will simply import the Nix expression given a path.
+- because of the functional paradigm, you'll often see the builtin used with the parameters in one go — e.g., ~import <nixpkgs> {  }~ which will import nixpkgs from one of the module paths with the default attribute set.
 
-- [[id:8f23f862-a19a-4a13-8d8f-69c280a8e072][Nix derivations]] are one of the central components of the package manager
-- =mkDerivation=
-- derivations are more verbose than necessary, most of the packaging process are done with the =nixpkgs= which contains a standard library to easily create derivations with different setups from programming languages and frameworks
 
 
 
@@ -37,4 +43,4 @@ This is just a personal reference note, the recommended resource for learning th
 
 - nixpkgs has a standard library that comes with functions mitigating against the verbosity for packaging or simply convenience
 
-* TODO Imports
+-
diff --git a/notebook/packages.nix.org b/notebook/packages.nix.org
index a78a1b1..671b3f6 100644
--- a/notebook/packages.nix.org
+++ b/notebook/packages.nix.org
@@ -3,7 +3,7 @@
 :END:
 #+title: Nix packages
 #+date: 2021-07-18 21:23:26 +08:00
-#+date_modified: 2021-07-18 21:23:26 +08:00
+#+date_modified: 2021-12-12 23:48:08 +08:00
 #+language: en
 
 
@@ -13,3 +13,22 @@
 - for certain setups such as common conventions for certain programming languages like Rust and Go, nixpkgs has [[https://nixos.org/manual/nixpkgs/unstable/#chap-language-support][environments created for those]];
   different versions may have changes so be sure to go into the appropriate documentation and create packages for a specific channel;
   this is significantly easier with [[id:6873de22-9eac-492c-93a8-6cdf8cbfc0f8][Nix flakes]]
+
+* Ecosystems
+- while derivations can be interacted with the builtin function =builtins.derivation=, it isn't really recommended since it is very verbose;
+  instead, you use =stdenv.mkDerivation= from nixpkgs
+
+- nixpkgs is the official repository of NixOS containing the standard library extending the [[id:a57e63a7-6daa-4639-910d-c6648df156a3][Nix language]], the largest repository of packages (counting up to 80,000 as of 2021-12-12), and various NixOS modules used to build the system itself
+
+- nixpkgs contains =stdenv= which is a derivation meant to be a base for other packages
+  - stdenv contains base packages that virtually all packages have (inside nixpkgs)
+  -
+
+- =stdenv.mkDerivation= is a convenient way of creating derivations;
+  however, it is very abstract and a lot of events happening around it
+  - this is a function that accepts a large attribute set
+  - it will map its arguments corresponding to a parameter in the final derivation made with =stdenv= (which is a shell script)
+  - attributes are usually just variables;
+    this is especially prevelant if
+  - packages can also set setup hooks (i.e., =setupHook=) that are essentially shell scripts to be added in the final derivation
+    - example: [[https://github.com/NixOS/nixpkgs/tree/nixos-21.11/pkgs/development/tools/build-managers/cmake][cmake]], [[https://github.com/NixOS/nixpkgs/tree/nixos-21.11/pkgs/development/libraries/glib][glib]], and [[https://github.com/NixOS/nixpkgs/tree/nixos-21.11/pkgs/development/tools/build-managers][most of the build systems at nixpkgs]]
diff --git a/notebook/tools.nix.derivations.org b/notebook/tools.nix.derivations.org
index 403cbfc..f258125 100644
--- a/notebook/tools.nix.derivations.org
+++ b/notebook/tools.nix.derivations.org
@@ -3,7 +3,7 @@
 :END:
 #+title: Nix derivations
 #+date: 2021-07-18 23:16:39 +08:00
-#+date_modified: 2021-07-18 23:16:39 +08:00
+#+date_modified: 2021-12-28 00:16:07 +08:00
 #+language: en
 
 
@@ -13,41 +13,41 @@ At a glance, this is the equivalent to manifests from [[id:ecee1a61-3d5c-4c8f-a2
 The following code block shows what a derivation looks like.
 
 #+begin_src bash  :cache yes
-nix show-derivation nixpkgs.hello
+nix show-derivation nixpkgs#hello
 #+end_src
 
-#+results[e489b584c0de1eac206a48340452807005a9bf87]:
+#+results[41a57682cb5744db1bd748068384a6d4bc4702c5]:
 #+begin_example
 {
-  "/nix/store/7xcq1j6kxry9p5scmgccifqp1m57ha17-hello-2.10.drv": {
+  "/nix/store/vvb4wxmnjixmrkhmj2xb75z62hrr41i7-hello-2.10.drv": {
     "outputs": {
       "out": {
-        "path": "/nix/store/kzq2f6pqb3ig89278n3c21g6x4y3pghs-hello-2.10"
+        "path": "/nix/store/xcp9cav49dmsjbwdjlmkjxj10gkpx553-hello-2.10"
       }
     },
     "inputSrcs": [
       "/nix/store/9krlzvny65gdc8s7kpb6lkx8cd02c25b-default-builder.sh"
     ],
     "inputDrvs": {
-      "/nix/store/aq6m16jyrdpz2frivygw0502lkhyv271-stdenv-linux.drv": [
+      "/nix/store/127p1886lb1q7x02wyy77ib9ghhc324v-hello-2.10.tar.gz.drv": [
         "out"
       ],
-      "/nix/store/hhq1cbwwjm28bp7bnr9ivlvgah7988xb-hello-2.10.tar.gz.drv": [
+      "/nix/store/4lzwc3wzbqjq973psxkph8jjq4g6cssr-stdenv-linux.drv": [
         "out"
       ],
-      "/nix/store/mhgg30w6ayhbvnp03z8gx4c92n67ajg6-bash-4.4-p23.drv": [
+      "/nix/store/js6ib8zv84knb7kwnjdrqgwf86djjblk-bash-5.1-p12.drv": [
         "out"
       ]
     },
-    "platform": "x86_64-linux",
-    "builder": "/nix/store/26a78ync552m8j4sbjavhvkmnqir8c9y-bash-4.4-p23/bin/bash",
+    "system": "x86_64-linux",
+    "builder": "/nix/store/a54wrar1jym1d8yvlijq0l2gghmy8szz-bash-5.1-p12/bin/bash",
     "args": [
       "-e",
       "/nix/store/9krlzvny65gdc8s7kpb6lkx8cd02c25b-default-builder.sh"
     ],
     "env": {
       "buildInputs": "",
-      "builder": "/nix/store/26a78ync552m8j4sbjavhvkmnqir8c9y-bash-4.4-p23/bin/bash",
+      "builder": "/nix/store/a54wrar1jym1d8yvlijq0l2gghmy8szz-bash-5.1-p12/bin/bash",
       "configureFlags": "",
       "depsBuildBuild": "",
       "depsBuildBuildPropagated": "",
@@ -61,14 +61,14 @@ nix show-derivation nixpkgs.hello
       "doInstallCheck": "",
       "name": "hello-2.10",
       "nativeBuildInputs": "",
-      "out": "/nix/store/kzq2f6pqb3ig89278n3c21g6x4y3pghs-hello-2.10",
+      "out": "/nix/store/xcp9cav49dmsjbwdjlmkjxj10gkpx553-hello-2.10",
       "outputs": "out",
       "patches": "",
       "pname": "hello",
       "propagatedBuildInputs": "",
       "propagatedNativeBuildInputs": "",
       "src": "/nix/store/3x7dwzq014bblazs7kq20p9hyzz0qh8g-hello-2.10.tar.gz",
-      "stdenv": "/nix/store/dj40kjgp5lhs55v4hc47vyrarhq4qycz-stdenv-linux",
+      "stdenv": "/nix/store/xcmlbsqabmckx42p8w18ri5zq8v2iiav-stdenv-linux",
       "strictDeps": "",
       "system": "x86_64-linux",
       "version": "2.10"
@@ -77,9 +77,7 @@ nix show-derivation nixpkgs.hello
 }
 #+end_example
 
-While we can create derivations with the [[id:a57e63a7-6daa-4639-910d-c6648df156a3][Nix language]], it is unnecessary and verbose if we use nixpkgs.
-nixpkgs has made the process easier with their standard library.
+While we can create derivations with the =derivations= builtin from the [[id:a57e63a7-6daa-4639-910d-c6648df156a3][Nix language]], in practice you'll use =stdenv.mkDerivation= from nixpkgs standard library.
 
-- =stdenv.mkDerivation=
 - nixpkgs also comes with several convenient functions/environments for several programming languages and frameworks including Python, Rust, Go, and Nim
 - it also includes environments for common setups such as for clang compiler
diff --git a/notebook/tools.nix.flakes.org b/notebook/tools.nix.flakes.org
index fbdce39..a8fe2bd 100644
--- a/notebook/tools.nix.flakes.org
+++ b/notebook/tools.nix.flakes.org
@@ -3,7 +3,7 @@
 :END:
 #+title: Nix flakes
 #+date: 2021-07-18 22:34:11 +08:00
-#+date_modified: 2021-09-14 18:39:43 +08:00
+#+date_modified: 2021-12-28 21:12:39 +08:00
 #+language: en
 
 
@@ -11,96 +11,287 @@
 As of 2021-06-30, the version used for this note is at v2.3 so it needs to be invoked with the unstable version.
 #+end_note
 
-- similar to [[https://guix.gnu.org/manual/en/html_node/Channels.html][Guix channels]]
-- a collection of packages and functions while making it easy to configure Nix declaratively
-- replaces the traditional Nix channels since fully reproducing an environment with Nix requires special care in practice;
-  it isn't fully reproducible in practice such as the inclusion of Nix paths embedded in environment variables and access to arbitrary files;
-  plus, there's no standard way of composing projects with Nix
-- as of 2021-06-30, this is on the unstable version of the Nix package manager and needs some additional configuration
+What are Nix flakes?
 
-why flakes?
+A self-contained Nix module that takes inputs (can be from other flakes) and create outputs.
+It is comparable to [[https://guix.gnu.org/manual/en/html_node/Channels.html][Guix channels]] (or the NUR) in the way any arbitrary value can be exported, thus extending a Nix module in any direction the author can make it to.
+Also, it supercedes Nix channels as a way to manage your system.
 
-- provides a structure for discoverability
-- makes 100% reproducibility a little easier with Nix
-- in case you're using NixOS, it also provides an easier way to extend it with third-party custom modules
+So, why use flakes?
 
-Here's an example to interact with a flake.
-It will show the entire outputs of a flake as well as the normalized version of the flake object.
+- Since it is self-contained, it is easier to compose and develop environments for projects.
+- It is more declarative compared to Nix channels.
+- Provides a structure for discoverability through exploring the output.
+- In case you're using roam:NixOS, it also provides an easier way to extend it with third-party custom modules.
 
-#+name: flake-sample-object
-#+begin_src python  :results value silent :exports none
-return "github:edolstra/dwarffs"
+
+
+
+* Exploring a Nix flake
+
+To get started with a flake, you can quickly create one with =nix flake init=.
+This will create =flake.nix= which is also required for Nix to recognize the project as a flake.
+
+Here's the skeleton of a flake.
+
+#+begin_src nix
+{
+  description = "A basic flake.";
+  inputs = {};
+  outputs = {};
+}
 #+end_src
 
-#+begin_src shell  :shebang "#!/usr/bin/env nix-shell"
-#! nix-shell -i bash -p nixUnstable
-nix --experimental-features 'nix-command flakes' flake show <<flake-sample-object()>> | sed -e "s/\x1b\[.\{1,5\}m//g"
+It is really just an attribute set that mainly deals with three attributes:
+
+- =description= which is self-descriptive enough to see what's it for. ;p
+- =inputs= which contains inputs (that are other flakes) to be used for...
+- ...the =outputs= which is a function that returns an attribute set to be exported.
+
+Here's a real example of a basic flake.
+
+#+begin_src nix
+{
+  description = "A basic flake with some real inputs this time.";
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs";
+
+    home-manager.url = "github:nix-community/home-manager";
+    home-manager.inputs.nixpkgs.follows = "nixpkgs";
+  };
+  outputs = attrs@{ self, nixpkgs, home-manager, ... }: {
+    homeManagerConfiguration = import ./hmUsers;
+    packages.x86_64-linux = {
+      hello = nixpkgs.pkgs.hello;
+    };
+  };
+}
 #+end_src
 
-#+results:
+The flake requires other flakes from the nixpkgs and home-manager as indicated from the URL.
+This will get the latest revision of both inputs.
+
+This is not ideal as it will get the latest revisions every time it requests the inputs.
+While you can pin the version by adding more information (e.g., =nixpkgs.url = "github:NixOS/nixpkgs/nixos-21.11"=, =home-manager.url = "github:nix-community/home-manager/781d25b315def05cd7ede3765226c54216f0b1fe"=), this isn't really necessary for the most part as we have lockfiles to secure our dependencies version.
+These lockfiles can be found at =flake.lock= where complete metadata for the flakes are found.
+
+
+
+* Selected list of attributes for outputs
+
+While you can export attributes of any type, there are common attributes you'll mostly see.
+
+As an example, here's the flake of my NixOS configuration.
+
+#+begin_src shell  :cache yes  :results output
+nix flake show github:foo-dogsquared/nixos-config | nix run nixpkgs#gnused -- 's/\x1b\[[0-9;]*m//g'
+#+end_src
+
+#+results[cf6df0202da35fbba99f7581b2655fb75d9eef8a]:
 #+begin_example
-github:edolstra/dwarffs/f691e2c991e75edb22836f1dbe632c40324215c5
-├───checks
+github:foo-dogsquared/nixos-config/12077bfc601e5465e343e590a830e8d3cb6a1a59
+├───devShells
+│   ├───aarch64-darwin
+│   │   ├───flatpak: development environment 'nix-shell'
+│   │   ├───hugo: development environment 'nix-shell'
+│   │   └───rust: development environment 'nix-shell'
 │   ├───aarch64-linux
-│   │   ├───build: derivation 'dwarffs-0.1.20210121.f691e2c'
-│   │   └───test: derivation 'vm-test-run-unnamed'
+│   │   ├───flatpak: development environment 'nix-shell'
+│   │   ├───hugo: development environment 'nix-shell'
+│   │   └───rust: development environment 'nix-shell'
 │   ├───i686-linux
-│   │   ├───build: derivation 'dwarffs-0.1.20210121.f691e2c'
-│   │   └───test: derivation 'vm-test-run-unnamed'
+│   │   ├───flatpak: development environment 'nix-shell'
+│   │   ├───hugo: development environment 'nix-shell'
+│   │   └───rust: development environment 'nix-shell'
+│   ├───x86_64-darwin
+│   │   ├───flatpak: development environment 'nix-shell'
+│   │   ├───hugo: development environment 'nix-shell'
+│   │   └───rust: development environment 'nix-shell'
 │   └───x86_64-linux
-│       ├───build: derivation 'dwarffs-0.1.20210121.f691e2c'
-│       └───test: derivation 'vm-test-run-unnamed'
-├───defaultPackage
-│   ├───aarch64-linux: package 'dwarffs-0.1.20210121.f691e2c'
-│   ├───i686-linux: package 'dwarffs-0.1.20210121.f691e2c'
-│   └───x86_64-linux: package 'dwarffs-0.1.20210121.f691e2c'
+│       ├───flatpak: development environment 'nix-shell'
+│       ├───hugo: development environment 'nix-shell'
+│       └───rust: development environment 'nix-shell'
+├───homeManagerConfigurations: unknown
+├───homeManagerModules: unknown
+├───lib: unknown
+├───nixosConfigurations
+│   └───ni: NixOS configuration
 ├───nixosModules
-│   └───dwarffs: NixOS module
-└───overlay: Nixpkgs overlay
+│   ├───agenix: NixOS module
+│   ├───archiving: NixOS module
+│   ├───desktop: NixOS module
+│   ├───dev: NixOS module
+│   ├───hardware-setup: NixOS module
+│   ├───themes: NixOS module
+│   └───users: NixOS module
+└───packages
+    ├───aarch64-darwin
+    │   ├───doggo: package 'doggo-0.4.1'
+    │   ├───gnome-shell-extension-burn-my-windows: package 'gnome-shell-extension-burn-my-windows-2'
+    │   ├───gnome-shell-extension-desktop-cube: package 'gnome-shell-extension-desktop-cube-5'
+    │   ├───gnome-shell-extension-fly-pie: package 'gnome-shell-extension-fly-pie-12'
+    │   ├───gnome-shell-extension-pop-shell: package 'gnome-shell-extension-pop-shell-unstable-2021-11-30'
+    │   ├───libcs50: package 'libcs50-10.1.1'
+    │   ├───llama: package 'llama-1.0.2'
+    │   ├───neo: package 'neo-0.6'
+    │   ├───pop-launcher: package 'pop-launcher-1.1.0'
+    │   ├───pop-launcher-plugin-duckduckgo-bangs: package 'pop-launcher-plugin-duckduckgo-bangs-1.3.0'
+    │   ├───sioyek: package 'sioyek-1.0.0'
+    │   └───tic-80: package 'tic-80-unstable-2021-12-18'
+    ├───aarch64-linux
+    │   ├───doggo: package 'doggo-0.4.1'
+    │   ├───gnome-shell-extension-burn-my-windows: package 'gnome-shell-extension-burn-my-windows-2'
+    │   ├───gnome-shell-extension-desktop-cube: package 'gnome-shell-extension-desktop-cube-5'
+    │   ├───gnome-shell-extension-fly-pie: package 'gnome-shell-extension-fly-pie-12'
+    │   ├───gnome-shell-extension-pop-shell: package 'gnome-shell-extension-pop-shell-unstable-2021-11-30'
+    │   ├───libcs50: package 'libcs50-10.1.1'
+    │   ├───llama: package 'llama-1.0.2'
+    │   ├───neo: package 'neo-0.6'
+    │   ├───pop-launcher: package 'pop-launcher-1.1.0'
+    │   ├───pop-launcher-plugin-duckduckgo-bangs: package 'pop-launcher-plugin-duckduckgo-bangs-1.3.0'
+    │   ├───sioyek: package 'sioyek-1.0.0'
+    │   └───tic-80: package 'tic-80-unstable-2021-12-18'
+    ├───i686-linux
+    │   ├───doggo: package 'doggo-0.4.1'
+    │   ├───gnome-shell-extension-burn-my-windows: package 'gnome-shell-extension-burn-my-windows-2'
+    │   ├───gnome-shell-extension-desktop-cube: package 'gnome-shell-extension-desktop-cube-5'
+    │   ├───gnome-shell-extension-fly-pie: package 'gnome-shell-extension-fly-pie-12'
+    │   ├───gnome-shell-extension-pop-shell: package 'gnome-shell-extension-pop-shell-unstable-2021-11-30'
+    │   ├───libcs50: package 'libcs50-10.1.1'
+    │   ├───llama: package 'llama-1.0.2'
+    │   ├───neo: package 'neo-0.6'
+    │   ├───pop-launcher: package 'pop-launcher-1.1.0'
+    │   ├───pop-launcher-plugin-duckduckgo-bangs: package 'pop-launcher-plugin-duckduckgo-bangs-1.3.0'
+    │   ├───sioyek: package 'sioyek-1.0.0'
+    │   └───tic-80: package 'tic-80-unstable-2021-12-18'
+    ├───x86_64-darwin
+    │   ├───doggo: package 'doggo-0.4.1'
+    │   ├───gnome-shell-extension-burn-my-windows: package 'gnome-shell-extension-burn-my-windows-2'
+    │   ├───gnome-shell-extension-desktop-cube: package 'gnome-shell-extension-desktop-cube-5'
+    │   ├───gnome-shell-extension-fly-pie: package 'gnome-shell-extension-fly-pie-12'
+    │   ├───gnome-shell-extension-pop-shell: package 'gnome-shell-extension-pop-shell-unstable-2021-11-30'
+    │   ├───libcs50: package 'libcs50-10.1.1'
+    │   ├───llama: package 'llama-1.0.2'
+    │   ├───neo: package 'neo-0.6'
+    │   ├───pop-launcher: package 'pop-launcher-1.1.0'
+    │   ├───pop-launcher-plugin-duckduckgo-bangs: package 'pop-launcher-plugin-duckduckgo-bangs-1.3.0'
+    │   ├───sioyek: package 'sioyek-1.0.0'
+    │   └───tic-80: package 'tic-80-unstable-2021-12-18'
+    └───x86_64-linux
+        ├───doggo: package 'doggo-0.4.1'
+        ├───gnome-shell-extension-burn-my-windows: package 'gnome-shell-extension-burn-my-windows-2'
+        ├───gnome-shell-extension-desktop-cube: package 'gnome-shell-extension-desktop-cube-5'
+        ├───gnome-shell-extension-fly-pie: package 'gnome-shell-extension-fly-pie-12'
+        ├───gnome-shell-extension-pop-shell: package 'gnome-shell-extension-pop-shell-unstable-2021-11-30'
+        ├───libcs50: package 'libcs50-10.1.1'
+        ├───llama: package 'llama-1.0.2'
+        ├───neo: package 'neo-0.6'
+        ├───pop-launcher: package 'pop-launcher-1.1.0'
+        ├───pop-launcher-plugin-duckduckgo-bangs: package 'pop-launcher-plugin-duckduckgo-bangs-1.3.0'
+        ├───sioyek: package 'sioyek-1.0.0'
+        └───tic-80: package 'tic-80-unstable-2021-12-18'
 #+end_example
 
-Let's build from one of the outputs of call_flake-sample-object().
+- =defaultPackage.${system}.${package}= (or =packages.${system}.${package}=) is mainly expected for packages.
+  This allows for easy building — e.g., =nix build nixpkgs#hello= will refer to =defaultPackage.${system}.hello=.
+  Another command that expects this is =nix run ${PACKAGE}= (e.g., =nix run nixpkgs#hello=).
 
-#+begin_src shell  :shebang "#!/usr/bin/env nix-shell"
-#! nix-shell -i bash -p nixUnstable
-nix --experimental-features 'nix-command flakes' build 'github:edolstra/dwarffs#checks.aarch64-linux.build'
+- =nixosConfigurations.${host}= is a NixOS host configuration.
+  Each attribute contain a set similar to the traditional set from =/etc/nixos/configuration.nix=.
+  This is very beneficial for quickly installing only with flakes — e.g., =nixos-install --flake github:foo-dogsquared/nixos-config#zilch= will install with =nixosConfigurations.zilch=.
+  However, attributes should be created with =lib.nixosSystem= from =nixpkgs= flake.
 
-nix --experimental-features 'nix-command flakes' shell 'github:edolstra/dwarffs' --command dwarffs --version
+- =nixosModules.${module}= is a [[roam:NixOS modules]], allowing you to extend NixOS further.
+  These are expected to be similar NixOS modules from nixpkgs.
+
+- =templates.${name}= is a template that has the attribute =path= and =description=.
+  See [[Flake templates]] for more details about how it's used.
+
+- =devShell.${system}= is expected to be a derivation (mostly with =mkShell=).
+  This is the default development environment to be used.
+  This is mostly expected for projects providing an easy way to bootstrap for development (e.g., with =nix develop ${FLAKE}=).
+
+- =devShells.${system}.${name}= is an attribute set of derivations (mostly from =mkShell=).
+  This is similar to =devShell= except this is where =nix develop= subcommand finds if an attribute name is given.
+
+
+
+
+* Flake templates
+
+- Flakes can have templates to get started with.
+  They can be used with =nix flake init ${TEMPLATE}=.
+
+- You can export it in your flakes through the =templates= attribute.
+  =templates= is expected to be an attribute set with each attribute representing a template.
+
+- By default, we have the =templates= flake from the global registry pointed to [[https://github.com/NixOS/templates][NixOS/templates]] Git repo.
+
+
+
+
+* Nix registry
+
+Per the Nix manual:
+
+#+begin_quote
+Flake registries are a convenience feature that allows you to refer to flakes using symbolic identifiers such as =nixpkgs=, rather than full URLs such as =git://github.com/NixOS/nixpkgs=.
+#+end_quote
+
+Here's an example of the registry list with some overriden flakes such as the =nixpkgs= flake following from my [[https://github.com/foo-dogsquared/nixos-config][NixOS configuration]].
+
+#+begin_src shell  :cache yes
+nix registry list
 #+end_src
 
-#+results:
-: fusermount version: 2.9.9
-
-For full reproducibility, you can refer to specific point of a flake (e.g., commit).
-
-#+begin_tip
-To easily get a pinned URL, you can run =flake metadata= subcommand.
-
-#+begin_src shell  :shebang "#!/usr/bin/env nix-shell"
-#! nix-shell -i bash -p nixUnstable
-nix --experimental-features 'nix-command flakes' flake metadata 'github:edolstra/dwarffs' | sed -e "s/\x1b\[.\{1,5\}m//g"
-#+end_src
-
-#+results:
+#+results[2e793be4dcc8dcc2f0c921da5dffa1544455d14e]:
 #+begin_example
-Resolved URL:  github:edolstra/dwarffs
-Locked URL:    github:edolstra/dwarffs/f691e2c991e75edb22836f1dbe632c40324215c5
-Description:   A filesystem that fetches DWARF debug info from the Internet on demand
-Path:          /nix/store/769s05vjydmc2lcf6b02az28wsa9ixh1-source
-Revision:      f691e2c991e75edb22836f1dbe632c40324215c5
-Last modified: 2021-01-21 22:41:26
-Inputs:
-├───nix: github:NixOS/nix/6254b1f5d298ff73127d7b0f0da48f142bdc753c
-│   ├───lowdown-src: github:kristapsdz/lowdown/1705b4a26fbf065d9574dce47a94e8c7c79e052f
-│   └───nixpkgs: github:NixOS/nixpkgs/ad0d20345219790533ebe06571f82ed6b034db31
-└───nixpkgs follows input 'nix/nixpkgs'
+system flake:agenix path:/nix/store/yka795vkb7ny5fnybf8dafbypcjfmi9n-source?lastModified=1638837456&narHash=sha256-WHLOxthAGx%2fwXw3QUa%2flFE3mr6cQtnXfFYZ0DNyYwt4=&rev=57806bf7e340f4cae705c91748d4fdf8519293a9
+system flake:config path:/nix/store/3nlagaj6748w4ffxx4vp5jss2k571f8i-source?lastModified=1640442672&narHash=sha256-Gkt2On9szrFlOo6QiYMOA90qTp4PICd7STHFhGA4bCs=
+system flake:home-manager path:/nix/store/ijh6v700kpssfyw44v4awbm2gmjx26qs-source?lastModified=1640296831&narHash=sha256-Mu32vTcfZru4VrvgnpvQKmwC4uY0oF3vnnC2o9SgnRU=&rev=f15b151ca1c4aea23515c241051d71f1b5cf97c8
+system flake:nixpkgs path:/nix/store/lgfhg4n6445yizgf0xjirb4bc4j86fr9-source?lastModified=1640269308&narHash=sha256-vBVwv3+kPrxbNyfo48cB5cc5%2f4tq5zlJGas%2fqw8XNBE=&rev=0c408a087b4751c887e463e3848512c12017be25
+global flake:agda github:agda/agda
+global flake:blender-bin github:edolstra/nix-warez?dir=blender
+global flake:dreampkgs github:nix-community/dreampkgs
+global flake:dwarffs github:edolstra/dwarffs
+global flake:fenix github:nix-community/fenix
+global flake:flake-utils github:flake-utils/numtide
+global flake:gemini github:nix-community/flake-gemini
+global flake:home-manager github:nix-community/home-manager
+global flake:hydra github:NixOS/hydra
+global flake:mach-nix github:DavHau/mach-nix
+global flake:nimble github:nix-community/flake-nimble
+global flake:nix github:NixOS/nix
+global flake:nixops github:NixOS/nixops
+global flake:nixos-hardware github:NixOS/nixos-hardware
+global flake:nixos-homepage github:NixOS/nixos-homepage/flake
+global flake:nur github:nix-community/NUR
+global flake:nixpkgs github:NixOS/nixpkgs/nixpkgs-unstable
+global flake:templates github:NixOS/templates
+global flake:patchelf github:NixOS/patchelf
+global flake:nix-serve github:edolstra/nix-serve
+global flake:nickel github:tweag/nickel
 #+end_example
-#+end_tip
 
-#+begin_src shell  :shebang "#!/usr/bin/env nix-shell"
-#! nix-shell -i bash -p nixUnstable
-nix --experimental-features 'nix-command flakes' shell github:edolstra/dwarffs/f691e2c991e75edb22836f1dbe632c40324215c5 --command dwarffs --version
-#+end_src
+So how does a flake registry work?
 
-#+results:
-: fusermount version: 2.9.9
+- It is managed through =nix registry= subcommand or set =nix.registry= in your system configuration.
+
+- Registries are primarily written as JSON files in certain files (e.g., =$XDG_CONFIG_HOME/nix/registry=, =/etc/nix/registry.json=).
+  For more information, see the [[https://nixos.org/manual/nix/stable/command-ref/new-cli/nix3-registry.html#registry-format][registry format from the manual]].
+  Unlike the traditional Nix channels, the inclusion of arbitrary files and their locations doesn't seem to affect the reproducibility since it is mostly used as a convenience feature after all.
+
+- The flakes from default registry are mostly getting the latest revisions of the flake per invocation so it is best practice to pin them (e.g., =nix registry pin=, through =nix.registry= while setting the NixOS systems in =flake.nix=).
+
+- There are primarily three registries to worry about: user, system, and global.
+
+- This is also the reason it downloads something why each time you invoke a Nix-related command (e.g., =nix search=, =nix edit=).
+  [fn:: I think pinning the flakes from the global registry will simply resolve this issue.]
+
+
+
+
+* More information about flakes
+
+- We can modify our inputs.
+  In the above example, we made =home-manager= to use our version of =nixpkgs= which will make it easier to sync.