I want to run the following on ubunt 20.04:

sh <(curl -L https://nixos.org/nix/install) --daemon

what I got is this:

sh <(curl -L https://nixos.org/nix/install) --daemon
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
100  4046  100  4046    0     0  16782      0 --:--:-- --:--:-- --:--:--   98k
downloading Nix 2.5.1 binary tarball for x86_64-linux from 'https://releases.nixos.org/nix/nix-2.5.1/nix-2.5.1-x86_64-linux.tar.xz' to '/tmp/nix-binary-tarball-unpack.KPhkYw21Nn'...
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0Warning: Failed to create the file 
Warning: /tmp/nix-binary-tarball-unpack.KPhkYw21Nn/nix-2.5.1-x86_64-linux.tar.x
Warning: z: No such file or directory
  0 27.1M    0  1103    0     0  10753      0  0:44:05 --:--:--  0:44:05 10813
curl: (23) Failure writing output to destination
/dev/fd/63: failed to download 'https://releases.nixos.org/nix/nix-2.5.1/nix-2.5.1-x86_64-linux.tar.xz'

When I have a look at /dev/fd/ I see a bunch of files marked inaccessible:

enter image description here

I guess this has something to do with the failure to download. Am I right? What can I do against it? I am just a 'normal' ubuntu user, this kind of stuff exceeds my ubuntu-knowledge.

UPDATE: Even if I run the whole thing as root the result remains the same:

enter image description here

  • 2
    Probably you have to download inside your home folder, where you have enough permissions. Also note that /dev/fb/ and /dev/fd/ are different objects. Which guide do you follow? Do you have sudo permissions on this computer?
    – N0rbert
    Jan 14 at 17:40
  • Try adding the option -s to curl. Maybe then you will notice this: "Warning: Failed to create the file" and "Failure writing output to destination" .
    – Luuk
    Jan 14 at 18:31
  • @N0rbert, yes, I do have sudo permission, but id does not seem to help. I am trying to follow this : nixos.org/download.html. Forgive me for my stupid question, but I am now in pr@server (probably due to a earlier installation which no longer matters).From here how to get to get to pr@home, or home?
    – Sanyifejű
    Jan 14 at 18:57
  • @Luuk sh <(curl -s -L nixos.org/nix/install) --daemon Unfortunately makes no difference
    – Sanyifejű
    Jan 14 at 19:00
  • 1
    You can enter exit to exit from SSH session. Or simply open new local terminal instance with Ctrl+Alt+T.
    – N0rbert
    Jan 14 at 19:08

1 Answer 1


After a very long research I found a useful hint.

Can't write to a hidden path using Curl

Basically snap curl is useless. Uninstall it properly. Get the proper apt curl, and everything works like a charm.

$ sudo snap remove curl
$ sudo apt install curl

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