Nix package manager
This discussion article is to cover the usage, internals and configuration of the Nix package manager.
Usage
Installation
This section described common methods for installing Nix on Non-NixOS distributions. For alternative installation methods, see the Nix Cookbook.
Install Nix for a single user
To install Nix from any Linux distribution, use the following two commands (assumes you have the permission to use sudo and you are logged in as the user you want to install Nix for).
$ sudo install -d -m755 -o $USER -g $USER /nix
$ curl https://nixos.org/nix/install | sh
After that being done, you can use all Nix commands as a normal user without any special permissions (for example by using sudo
)
Install Nix without root permissions
By using nix-user-chroot or PRoot
you can use Nix on systems, where you have no permission to create `/nix`.
nix-user-chroot
is the preferred and faster option. However it might not run on older linux kernels
or kernels without user namespace support. With the following command you can test
whether your system support user namespaces:
$ unshare --user --pid echo YES
The output should be YES
.
If the command is absent an alternative is to check the kernel compile options.
$ zgrep CONFIG_USER_NS /proc/config.gz
# On some systems like Debian or Ubuntu the kernel configuration is in a different place
$ grep CONFIG_USER_NS /boot/config-$(uname -r)
If the output of this command is CONFIG_USER_NS=y
your system supports user namespaces.
Internals
Development
History
Sandbox builds
When sandbox builds are enabled,
Nix will setup an isolated environment for each build process.
It is used to remove further hidden dependencies set by the build environment to improve reproducibility.
This includes access to the network during the build outside of fetch*
functions and files outside the Nix store.
Depending on the operating system access to other resources are blocked as well (ex. inter process communication is isolated on Linux);
see build-use-sandbox in nix manual for details.
Sandboxes are not enabled by default in Nix as there are cases where it makes building packages harder (for example npm install
will not work due missing network access).
In pull requests for nixpkgs people are asked to test builds with sandboxing enabled (see Tested using sandboxing
in the pull request template) because in official hydra builds sandboxing is also used.
Depending if you use NixOS or other platforms you can use one of the following methods to enable sandboxing.
Enable sandbox builds in NixOS
In configuration.nix
put
nix.useSandbox = true;
Enable sandbox builds on Non-NixOS platforms
In /etc/nix/nix.conf
put
build-use-sandbox = true
Common Errors
Bad configuration option: gssapikexalgorithms
Found when using an SSH binary from Nix on typically RPM-based distros like CentOS, Fedora, Scientific Linux, Redhat, etc. The quick fix: Just comment out the configuration option in the ssh config file, you probably don't need it.
Desktop Environment does not find .desktop files
IF your DE does not look in $HOME/.nix-profile/share
for .desktop files.
You need to add that path to the XDG_DATA_DIRS
, the position reflects precedence so files in earlier directories shadow files in later directories. This can be accomplished in various ways depending on your login manager, see Arch wiki: Xprofile for more information.
For example using ~/.xprofile
as follows:
$ export XDG_DATA_DIRS=$HOME/.nix-profile/share:/usr/local/share:/usr/share
Notice that you have to include the default locations on your system, otherwise they will be overwritten. Find out the proper paths using echo $XDG_DATA_DIRS
. (Note: export XDG_DATA_DIRS=$HOME/.nix-profile/share:$XDG_DATA_DIRS
did not work, XDG_DATA_DIRS ended up containing only $HOME/.nix-profile/share:
which isn't even a valid path.)