46 lines
1.4 KiB
Markdown
46 lines
1.4 KiB
Markdown
# Overrides
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By default, the NixOS systems are based on the latest release. While it is
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trivial to change this to nixos-unstable or any other branch of nixpkgs by
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changing the flake url, sometimes all we want is a single package from another
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branch.
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This is what the overrides are for. By default, they are pulled directly from
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nixpkgs/master, but you can change the `override` flake input url to
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nixos-unstable, or even a specific sha revision.
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## Example
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### Packages
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The override packages are defined as a regular overlay with an extra arguement
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`pkgs`. This refers to the packages built from the `override` flake.
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Pulling the manix package from the override flake:
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```nix
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{
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packages = pkgs: final: prev: {
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inherit (pkgs) manix;
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};
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}
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```
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### Modules
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You can also pull modules from override. Simply specify their path relative to
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the nixpkgs [modules][nixpkgs-modules] directory. The old version will be added
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to `disabledModules` and the new version imported into the configuration.
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Pulling the zsh module from the override flake:
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```nix
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{
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modules = [ "programs/zsh/zsh.nix" ];
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}
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```
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> ##### _Note:_
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> Sometimes a modules name will change from one branch to another. This is what
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> the `disabledModules` list is for. If the module name changes, the old
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> version will not automatically be disabled, so simply put it's old name in
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> this list to disable it.
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[nixpkgs-modules]: https://github.com/NixOS/nixpkgs/tree/master/nixos/modules
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