wiki/notebook/tools.nix.overrides-and-overlays.org

:PROPERTIES:
:ID:       8568ce92-99a8-4d20-9723-eee41a507327
:END:
#+title: nixpkgs overrides and overlays
#+date: 2021-07-28 12:54:40 +08:00
#+date_modified: 2022-09-03 20:26:34 +08:00
#+language: en


You can override values in [[id:f884a71c-0a0f-4fd7-82ff-00674ed4bd66][nixpkgs]] as a way to customize nixpkgs.
For example, if you want to use a different version from the nixpkgs channel, you can change the appropriate value.

#+begin_src nix
let overlay = self: super:
      {
        ncmpcpp = super.ncmpcpp.override { visualizerSupport = true; };
      }
#+end_src

For another example, you can see some examples from [[https://github.com/neovim/neovim/blob/f695457f815544d0dc16469569c70556e3165bb6/contrib/flake.nix][Neovim]] and [[https://gitlab.com/veloren/veloren/-/tree/685f4971ac0deb31b301e9d2bc0201d2531fd895/nix][Veloren]] (which also uses Nix flakes).

You can set overlays automatically either by setting =nixpkgs.overlays= from your system configuration or =~/.config/nixpkgs/overlays/= folder for user-specific settings.
You could also set overlays for standalone Nix code similarly through the =overlays= key — e.g., ~import <nixpkgs> ? { overlays = (self: super: { } ); };~.
Update the notebook The topics I've covered so far for Linux, package managers, archiving, and learning. I also updated some formatting for other notes especially with the command line references. 2021-07-29 15:26:51 +00:00			`:PROPERTIES:`
			`:ID: 8568ce92-99a8-4d20-9723-eee41a507327`
			`:END:`
Revise Nix-related notes Added more notes as I developed the Guix overlay for NixOS over time. It does have a nice experience, overall (albeit clunky one due to the documentation). 2022-10-25 08:58:19 +00:00			`#+title: nixpkgs overrides and overlays`
Update the notebook The topics I've covered so far for Linux, package managers, archiving, and learning. I also updated some formatting for other notes especially with the command line references. 2021-07-29 15:26:51 +00:00			`#+date: 2021-07-28 12:54:40 +08:00`
Revise Nix-related notes Added more notes as I developed the Guix overlay for NixOS over time. It does have a nice experience, overall (albeit clunky one due to the documentation). 2022-10-25 08:58:19 +00:00			`#+date_modified: 2022-09-03 20:26:34 +08:00`
Update the notebook The topics I've covered so far for Linux, package managers, archiving, and learning. I also updated some formatting for other notes especially with the command line references. 2021-07-29 15:26:51 +00:00			`#+language: en`


Revise Nix-related notes Added more notes as I developed the Guix overlay for NixOS over time. It does have a nice experience, overall (albeit clunky one due to the documentation). 2022-10-25 08:58:19 +00:00			`You can override values in [[id:f884a71c-0a0f-4fd7-82ff-00674ed4bd66][nixpkgs]] as a way to customize nixpkgs.`
Update the notebook The topics I've covered so far for Linux, package managers, archiving, and learning. I also updated some formatting for other notes especially with the command line references. 2021-07-29 15:26:51 +00:00			`For example, if you want to use a different version from the nixpkgs channel, you can change the appropriate value.`

			`#+begin_src nix`
			`let overlay = self: super:`
			`{`
			`ncmpcpp = super.ncmpcpp.override { visualizerSupport = true; };`
			`}`
			`#+end_src`

			`For another example, you can see some examples from [[https://github.com/neovim/neovim/blob/f695457f815544d0dc16469569c70556e3165bb6/contrib/flake.nix][Neovim]] and [[https://gitlab.com/veloren/veloren/-/tree/685f4971ac0deb31b301e9d2bc0201d2531fd895/nix][Veloren]] (which also uses Nix flakes).`

			`You can set overlays automatically either by setting =nixpkgs.overlays= from your system configuration or =~/.config/nixpkgs/overlays/= folder for user-specific settings.`
			`You could also set overlays for standalone Nix code similarly through the =overlays= key — e.g., ~import <nixpkgs> ? { overlays = (self: super: { } ); };~.`