Custom user configuration

Caution

⚠️ Caution: Modifying the file /etc/nixos/customConfig/default.nix is at your own risk. Only do so if you know what you are doing! ⚠️

GLF-OS provides a space to add your custom configurations in /etc/nixos/customConfig/default.nix

If the current configuration and flatpaks do not fully meet your needs, you can modify the configuration.

Adding an application present in the Nix repositories.

Note

Please note that you can find a large number of applications at the following link:
https://search.nixos.org/packages

Here is a practical example: we are going to add Google Chrome.

The option to install Google Chrome is pkgs.google-chrome, which can be found here : https://search.nixos.org/packages?channel=25.05&from=0&size=50&sort=relevance&type=packages&query=google-chrome

1- Open the file `/etc/nixos/customConfig/default.nix`. The Gnome Text Editor tool will do the job.

2 -Add `pkgs.google-chrome` below the comment # Add your stable apps here (example: pkgs.btop)

{
  lib,
  config,
  pkgs,
  pkgs-unstable,
  ...
}:

{
  environment.systemPackages = [
  # Add your stable apps here (exemple: pkgs.btop)
    pkgs.google-chrome


  # Add your unstable apps here (exemple: pkgs-unstable.btop)


  ];


  # Add your custom configuration here ↓

}

3- Save your file with `CTRL+S`; you will be asked for the root password.

4- Run the command with the terminal:

glf-update

5- Reboot your machine

Add a custom configuration.

If you now want to open specific ports in the firewall, this is done in the configuration section of the same file /etc/nixos/customConfig/default.nix.

{
  lib,
  config,
  pkgs,
  pkgs-unstable,
  ...
}:

{
  environment.systemPackages = [
  # Add your stable apps here (exemple: pkgs.btop)
    pkgs.google-chrome


  # Add your unstable apps here (exemple: pkgs-unstable.btop)


  ];


  # Add your custom configuration here ↓
  networking.firewall.allowedTCPPortRanges = [
    { from = 51413; to = 51413; }
  ];

}

Save your file with CTRL+S, and you will be prompted for the root password.

Run the command:

glf-update

Reboot your machine

Understanding how your settings combine with ours

This is the most useful notion on this page, and it explains every example below.

NixOS does not read your file "after" ours in order to overwrite it: it merges them. What happens depends on the option type.

Option type	What happens
A list	your entries are added to ours, nothing is lost
A simple value (boolean, string, package)	conflict if we already set it, `lib.mkForce` is required

Extending an application GLF already provides

Note

You have nothing to remove on our side: your list is added to ours.

Take OBS Studio. GLF already declares four plugins, and adds more depending on your graphics card. To add your own, simply declare the list in your file:

{
  # Add your custom configuration here ↓
  programs.obs-studio.plugins = with pkgs.obs-studio-plugins; [
    obs-backgroundremoval
    obs-shaderfilter
    input-overlay
  ];
}

Caution

Three pitfalls to avoid:

do not redeclare enable or package, we already set them. Declaring package would conflict with our CUDA variant enabled on NVIDIA cards

the prefix is pkgs.obs-studio-plugins., not pkgs.: OBS plugins live in their own set

a plugin is tied to the OBS version. A plugin built for another version will not load

The same reasoning applies to Steam, whose compatibility tools we already populate. To add utilities to its environment:

{
  programs.steam.extraPackages = [
    pkgs.steamtinkerlaunch
    pkgs.protontricks
  ];
}

Changing a value GLF already set

Here merging is not enough: two simple values conflict and evaluation fails. lib.mkForce settles it in your favour.

{
  fonts.fontconfig.defaultFonts.monospace = lib.mkForce [ "JetBrainsMono Nerd Font" ];
}

Note

Without lib.mkForce you will get an error such as "The option has conflicting definition values". That message does not mean you did something wrong: it simply asks you to say which definition wins.

Disabling a GLF component

Each major component exposes a switch, already listed as a comment in your file:

{
  glf.firefox.enable = lib.mkForce false;   # remove Firefox
  glf.gaming.enable = lib.mkForce false;    # remove the whole gaming pack
  glf.printing.enable = lib.mkForce false;  # remove printing
}

Note

For individual applications, prefer GLF Customizer: it writes to a file meant for that purpose and avoids conflicts.

Modifying a package itself

When no option exists, act on the package.

{
  environment.systemPackages = [
    (pkgs.mpv.override { scripts = [ pkgs.mpvScripts.mpris ]; })
  ];
}

Caution

The package no longer matches the one in the binary cache, so it will be rebuilt on your machine. Plan for the time it takes.

Finding options and packages

An option on search.nixos.org/options. The displayed type immediately tells you whether it merges (a list) or conflicts (a simple value)
A package on search.nixos.org/packages, or from the command line with nix search nixpkgs obs-studio-plugins
What GLF already declares, so you do not conflict with it: nixos-option programs.obs-studio.plugins

Going further, on the NixOS side

Modules and options: how options are declared and merged, the source of everything above
Priorities and mkForce: why and how to settle a conflict
Overriding packages: override and overrideAttrs
Overlays: replacing a package everywhere at once

If something goes wrong

Note

A failed evaluation installs nothing: your system stays exactly as it was. You cannot break it by trying.

If a boot goes wrong after a change, pick the previous generation in the boot menu, it is always there.

To roll back without rebooting:

sudo nixos-rebuild switch --rollback

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⚠️ Caution: Modifying the file /etc/nixos/customConfig/default.nix is at your own risk. Only do so if you know what you are doing! ⚠️