[Nix-dev] how to install nilfs-utils ?

[Tim Barbour]

I am trying to install nilfs-utils.

According to the wiki ( http://nixos.org/wiki/Install/remove_software ), I can
install a package by 'nix-env -i <package> for one user, or I can install it
for all users by adding it to environment.systemPackages . The second way does
not work for me for nilfs-utils. If I put

  environment.systemPackages = with pkgs; [
     wget httpfs2
     nilfs-utils
  ];

in /etc/nixos/configuration.nix, then nix complains:

$ nixos-rebuild build
building Nix...
building the system configuration...
error: undefined variable `nilfs-utils'

but other packages like wget or httpfs2 are fine.
Also 'nix-env -i nilfs-utils' works fine.

What is wrong with putting nilfs-utils in environment.systemPackages ?
Does it have something to do with the hyphen in the name, or is nilfs-utils a
special kind of package ? In the latter case, how can one tell ?
How can it be installed for all users ?

Tim
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