How do I upgrade my system to nixos-unstable?

Question

How do I make sure that all packages I install on my system nixos installation (i.e. packages listed in /etc/nixos/configuration.nix, which I install using sudo nixos-rebuild switch) are using the latest (unstable) version of nixos/nixpkgs?

Answer 1

As explained in the manual's section on upgrading, if you issue the following command as root:

nix-channel --list 

you will most likely see something like the following (if you were following the 16.09 branch for instance):

nixos https://nixos.org/channels/nixos-16.09 

By issuing the following command (still as root):

nix-channel --add https://nixos.org/channels/nixos-unstable nixos 

you will remove the 16.09 channel and replace it with nixos-unstable.

Now this is not enough yet. To really update your system, you need one last command:

nixos-rebuild switch --upgrade 

which is going to rebuild your system with your current configuration and updated packages from the channel you switched to.

Answer 2

Run the following commands:

sudo nix-channel --add https://nixos.org/channels/nixos-unstable sudo nix-channel --add https://nixos.org/channels/nixpkgs-unstable 

Note that the sudo is required: if you don't use sudo, it will only affect user-level packages (i.e. things you install using nix-env -i), not system-level packages.