lets do `nix-channel --update` and see if everything still works....

well...

+ had to install new nix
+ first I ran out of diskspace...
+ nix-env to delete old generations
+ commented out most of home.nix
+ nix-collect-garbage
+ nix-store --optimise
+ watched my diskspace go up and down like a yoyo

Now nix commands do not have man pages...

At least everything else appears to be working and I have freed up a bit more space….