Hmm.. could it be that your system is confused by multiple channels ? What's the output of (normal user) $ nix-channel --list
I think your best bet is `nix-shell "<nixpkgs>" -p letsencrypt` where nixpkgs is your channel name. You can even go further and set the nixpkgs path directly using nix-shell /nix/store/7kxsv9svwcaxzkxxjg0zxcb151mic8vw-nixos-16.03pre76756.885acea/nixos/nixpkgs -p letsencrypt nix-env can also take such a path To inspect your system state, try to run $ nix-instantiate --eval --expr --strict "<nixpkgs>" $ nix-instantiate --eval --expr --strict "<nixos>" $ sudo nix-instantiate --eval --expr --strict "<nixpkgs>" $ sudo nix-instantiate --eval --expr --strict "<nixos>" <nixpkgs> gets evaluated in the context of the current user, so you will get very different results when using sudo. To ensure a consistent result, you can also pass the nixpkg tree to nix-env with option -f. $ nix-env -qaP -f "<nixpkgs>" Now, there is no reason for the attribute returned by `nix-env -f "<nixpkgs>" -qaP` to be missing when calling `nix-shell "<nixpkgs>" -p` because the nixpkgs are exactly the same. All this highlights the inconsistency between (and within) the tools. But that's another story :-). Layus. Le 31/03/16 11:25, Dmitry Malikov a écrit : > >> nix-shell -p nixpkgs.pkgs.letsencrypt > error: undefined variable ‘nixpkgs’ at (string):1:66 > (use ‘--show-trace’ to show detailed location information) > > Any other ideas? > > On 31 March 2016 at 10:37, Arseniy Seroka <[email protected] > <mailto:[email protected]>> wrote: > > nix-shell -p nixpkgs.pkgs.letsencrypt > > -- > Sincerely, > Arseniy Seroka > > On 31 March 2016 02:21:40 Dmitry Malikov <[email protected] > <mailto:[email protected]>> wrote: > >> >> sudo nix-channel --list >> nixpkgs https://nixos.org/channels/nixpkgs-unstable >> nixos https://nixos.org/channels/nixos-15.09 >> >> >> nixos-version >> 15.09.1180.e8e1cb8 (Dingo) >> >> >> nix-env --version >> nix-env (Nix) 1.10 >> >> Anything else? >> >>> On 31 Mar 2016, at 00:45, Jonn Mostovoy <[email protected] >>> <mailto:[email protected]>> wrote: >>> >>> Just worked for me, exactly the same command. >>> My version of nixpkgs is way older though. >>> >>> On Mar 31, 2016 12:40 AM, "Dmitry Malikov" >>> <[email protected] <mailto:[email protected]>> wrote: >>> >>> >> >>> nix-env -qaP '*' | grep letsencrypt >>> nixpkgs.letsencrypt >>> >>> letsencrypt-0.4.0 >>> >>> >> nix-shell -p letsencrypt >>> error: undefined variable ‘letsencrypt’ at (string):1:66 >>> (use ‘--show-trace’ to show detailed location information) >>> >>> >>> What am I missing here? >>> >>> _______________________________________________ >>> nix-dev mailing list >>> [email protected] <mailto:[email protected]> >>> http://lists.science.uu.nl/mailman/listinfo/nix-dev >>> >> >> _______________________________________________ >> nix-dev mailing list >> [email protected] <mailto:nix-dev%40lists.science.uu.nl> >> http://lists.science.uu.nl/mailman/listinfo/nix-dev >> > > > > _______________________________________________ > nix-dev mailing list > [email protected] > http://lists.science.uu.nl/mailman/listinfo/nix-dev
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