Nix
Nix is a purely functional package manager that aims to make package management reliable and reproducible.
Installation
There are two choices for a Nix installation, one is supported by Arch Linux, and the other is officially supported by Nix.
Native
Upstream installation script
Download the file with curl --proto '=https' --tlsv1.2 -sSfL https://nixos.org/nix/install -o nix-install.sh, view it: less ./nix-install.sh, and run the script ./nix-install.sh --daemon to start Nix installation.
curl some-url | sh, as the Nix documentation suggests, is considered as a security risk, because it executes unknown code, that might even be corrupted during the download. Therefore it is recommended to manually download the script and check it, before executing it.Configuration
To have the Nix daemon launched at boot time, enable nix-daemon.service.
Add required users to the nix-users group in order to access the daemon socket.
Add a channel and update it.
$ nix-channel --add https://nixos.org/channels/nixpkgs-unstable $ nix-channel --update
Tips and tricks
With the shell configured, the following should install hello into your updated PATH: /nix/store/[hash]-hello-[version]/bin/hello.
If you installed Nix from the official repositories, you must add the ~/.nix-profile/bin directory to your PATH manually.
$ nix-env -iA nixpkgs.hello
Run hello and make sure it is in the right PATH. If it works, you can remove it simply by
$ nix-env --uninstall hello
Or you can check the list of installed program by (q stands for query)
$ nix-env -q
You can also check generations by
$ nix-env --list-generations
Check more details in the nix-env(1) manual.
Max jobs
By default, nix only uses one builder. The following will allow nix to use as many jobs as the number of CPUs:
/etc/nix/nix.conf
max-jobs = auto
Troubleshooting
Permission denied
Running nix repl or nix-env -u as user produces
cannot connect to daemon at '/nix/var/nix/daemon-socket/socket: permission denied
If you just installed nix, you need to reboot.
Too many open files
Some builds may run into an error such as
error: opening directory '/nix/store/...': Too many open files
Edit nix-daemon.service and increase the file limit
[Service] LimitNOFILE=65536
Warning message about root user channels
warning: Nix search path entry '/nix/var/nix/profiles/per-user/root/channels' does not exist, ignoring
If the above message shows up when using Nix, the root user will need to update their channels.
# nix-channel --update
Sandbox build issues
Broken coreutils
There is currently a problem with the /bin/sh provided by the nix package FS#73998 where the busybox provided coreutils override the build environment. One workaround is to install the nixpkgs busybox
# nix-build 'channel:nixpkgs-unstable' -A busybox-sandbox-shell --out-link /opt/busybox-nix
and update the nix configuration to use it
/etc/nix/nix.conf
sandbox-paths = /bin/sh=/opt/busybox-nix/bin/busybox
Other sandbox issues
error: while setting up the build environment: mounting /proc: Operation not permitted error: program '/usr/bin/nix-env' failed with exit code 1
1: package 'utils' in options("defaultPackages") was not found
2: package 'stats' in options("defaultPackages") was not found
Error: .onLoad failed in loadNamespace() for 'utils', details:
call: system(paste(which, shQuote(names[i])), intern = TRUE, ignore.stderr = TRUE)
error: cannot popen '/nix/store/fnkvlbls29d01jcx3wsdnhykyrl7087r-which-2.21/bin/which 'uname' 2>/dev/null', probable reason 'Cannot allocate memory'
The issue is known upstream: #2311, #3000, and #4636.
nixpkgs expects to be built with the sandbox on.The most common fix is to disable sandboxing in the configuration file, then Restart the nix-daemon service.
/etc/nix/nix.conf
# disable sandboxing sandbox = false