infinisil

with import ./lisp.nix { a = null; }; eval
(defun fib (n)
  (defun fib2 (a b n)
    (iff (lt n 2) b
      (def (next (plus a b))
      (fib2 b next (minus n 1))))
  (fib2 0 1 n))
(fib 60))

zimbatm

Nixpkgs pinning example

This is an example of how to pin the version of nixpkgs in a package repo. The goal is to improve reproducibility, make sure all the developers use the same version of nixpkgs and also allow to share binary caches.

Usage

Put all these files in a nixpkgs folder and then in other derivations, instead of import <nixpkgs> {} use import ./path/to/nixpkgs {}

Keeping nixpkgs up to date

bennofs

How X11 is started

In the following example, sddm will be used as a display manager. The process is however similar for other display managers in nixpkgs and a summary that applies to all nixpkgs display managers is given at the end.

1. Systemd unit "display-manager.service" starts services.x11.displayManager.job.execCmd (the display manager)

   Code reference: <nixpkgs>/nixos/modules/services/x11/xserver.nix

2. services.x11.displayManager.job.execCmd is set to the path of the sddm binary from the sddm package in the nix store. So SDDM will start and read its configuration from /etc/sddm.conf.

edk0

IRC friends, enemies and others,

Control of freenode has recently been seized by the proprietors of Freenode Limited, a holding company established by a previous head of freenode and a third party as part of a deal with a corporate sponsor. The terms of that deal were not disclosed, and remain unknown to me.

At the time, we, freenode's volunteer staff, were given informal guarantees that staff retained operational control of the network. The same guarantees were repeated after leadership was passed on to a new head of staff. I don't

widdowquinn

Turning emacs into a Python IDE

## Create a new config/initialisation file

Create a user-level initialisation file init.el:

touch .emacs.d/init.el

fasiha

Well, that was unexpected. In the following, I’m trying to follow Jon Evans’ advice from “The Terrible Technical Interview”.

---

To: recruitment@EmployerABC.com
From: Ahmed Fasih
Subject: Re: Programming Test Invitation

Hi there! Thanks for offering to let me take a HackerRank test for ABC, I appreciate the vote of confidence.

mbbx6spp

Cached and Persistent Nix shell with direnv integration

Problem being solved

• the default direnv Nix integration from projects loads a Nix shell every new terminal or every time shell.nix and/or default.nix changes. On larger projects with a lot of Nix shell dependencies, that can cause the terminal to take more than 6 seconds to load, which significantly degrades the developer experience (DX).
• when a developer garbage collects in their Nix store, often the Nix shell dependencies are deleted also which causes a slow start the next time the project’s Nix shell is requested, also degrading developer experience (DX).

Solution outline

• on first Nix shell load, the Nix shell is evaluated fully such that direnv dumps the environment from the spawn Nix shell process

LnL7

self: super:

{
  # Install overlay:
  # $ mkdir -p ~/.config/nixpkgs/overlays
  # $ curl https://gist.githubusercontent.com/LnL7/570349866bb69467d0caf5cb175faa74/raw/3f3d53fe8e8713ee321ee894ecf76edbcb0b3711/lnl-overlay.nix -o ~/.config/nixpkgs/overlays/lnl.nix
  userPackages = super.userPackages or {} // {

    # Example:
    hello = self.hello;

lheckemann

Expression for a buildEnv-based declarative user environment

This is one way of managing your user profile declaratively.

Alternatives include:

• an attrset-based nix-env-based environment, installed using nix-env -ir rather than nix-env --set. LnL has an overlay which shows a way of doing this.
• home-manager, which provides NixOS-like config for your $HOME

Note that this is incompatible with regular imperative use of nix-env, e.g. nix-env -iA nixpkgs.hello. It has the advantage of allowing the installation of multiple outputs of the same package much better than nix-env's builtin profile builder does.

fdaciuk

Github Two-Factor Authentication (2FA) for Brazil via SMS

The Github doesn't provide country code for Brazil (+55). To add this option, just run the code below in your console. The option Brazil +55 will be the first on the list, already selected:

---

🇧🇷 [pt-BR]

Autenticação em dois fatores (2FA) do GitHub para o Brasil via SMS