Nix: Replace channel with c when resolving URIs?

[Chakerbh]

My typical work day require me to build lot of packages with different nixpkgs versions. using -I nixpkgs=channel:nixos-18.03 is an awesome shortcut but I find myself typing it over and over again. Sometimes I even need two nixpkgs versions in the same build command!

I suggest to replace channel:nixos-18.03 with c:nixos-18.03 or even better -I nixpkgs=channel:nixos-18.03 with -I nixpkgs=18.03. I understand though that the latter can cause issues resolving local paths. And that it also incompatible with darwin channels.

[lheckemann]

While this doesn't address the issue within nix itself, you could also consider creating shell functions/wrappers like

with-18.03() {
  env "NIX_PATH=nixpkgs=channel:18.03:$NIX_PATH" -- "$@"
}

or a script (for use outside interactive shells) like

#!/bin/sh
exec env "NIX_PATH=nixpkgs=channel:18.03:$NIX_PATH" -- "$@"

to allow running commands like with-18.03 nix-build.