eh/README.md

eh - Ergonomic Nix CLI Helper

eh is a multicall ¹ (think Busybox) CLI tool that provides ergonomic shortcuts for common Nix commands with intelligent error handling, and more importantly, automatic fixes for common Nix errors.

Features

We provide a very tiny binary with a limited set of features. The most critical features are automatic hash fixes and auto-retry with appropriate environment variables.

Auto-Retry with Environment Variables

When a package fails to build due to licensing, security, stability, or whatever reason provided by Nixpkgs, eh equivalent of Nix commands retry automatically with the appropriate environment variables. While this is called automatic retry, we collect information about the packages from the meta field instead of building the package. The following variables are supported:

• Unfree packages: Sets NIXPKGS_ALLOW_UNFREE=1
• Insecure packages: Sets NIXPKGS_ALLOW_INSECURE=1
• Broken packages: Sets NIXPKGS_ALLOW_BROKEN=1

Hash Auto-Fix

When a hash mismatch is detected in the underlying nix build, eh can automatically update the old, broken hash with a new and correct one directly in the source file.

Shell Aliases

By default, you may run the eh binary akin to Nix with a nicer interface. The supported Nix commands, i.e., nix build, shell, run and develop become eh build, eh shell, eh run and eh develop. However, it is possible to symlink the eh binary to nb, ns, nr, and nd to invoke a specific feature. For example, nb will act as eh build and nr will be eh run.

One special example is eh update, which is aliases to nu, that handles interactive Nix flake updates. It is special in the sense that the usage is entirely different from its Nix counterpart, where you get to interactively pick which inputs to update.

After enabling shell aliases via the NixOS module or Home Manager, you can use:

ns nixpkgs#hello           # equivalent to: nix shell nixpkgs#hello
nr nixpkgs#cowsay "Hello!" # nix run nixpkgs#cowsay
nb .#myPackage             # nix build .#myPackage
nu                         # nix flake update

License

This project is made available under Mozilla Public License (MPL) version 2.0. See LICENSE for more details on the exact conditions. An online copy is provided here.

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1. See aliases section. ↩︎