Installing a Binary Distribution

The easiest way to install Nix is to run the following command:

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

This will run the installer interactively (causing it to explain what it is doing more explicitly), and perform the default "type" of install for your platform:

  • single-user on Linux

  • multi-user on macOS

    Notes on read-only filesystem root in macOS 10.15 Catalina +

    • It took some time to support this cleanly. You may see posts, examples, and tutorials using obsolete workarounds.
    • Supporting it cleanly made macOS installs too complex to qualify as single-user, so this type is no longer supported on macOS.

We recommend the multi-user install if it supports your platform and you can authenticate with sudo.

Single User Installation

To explicitly select a single-user installation on your system:

$ sh <(curl -L https://nixos.org/nix/install) --no-daemon

This will perform a single-user installation of Nix, meaning that /nix is owned by the invoking user. You should run this under your usual user account, not as root. The script will invoke sudo to create /nix if it doesn’t already exist. If you don’t have sudo, you should manually create /nix first as root, e.g.:

$ mkdir /nix
$ chown alice /nix

The install script will modify the first writable file from amongst .bash_profile, .bash_login and .profile to source ~/.nix-profile/etc/profile.d/nix.sh. You can set the NIX_INSTALLER_NO_MODIFY_PROFILE environment variable before executing the install script to disable this behaviour.

You can uninstall Nix simply by running:

$ rm -rf /nix

Multi User Installation

The multi-user Nix installation creates system users, and a system service for the Nix daemon.

Supported Systems

  • Linux running systemd, with SELinux disabled
  • macOS

You can instruct the installer to perform a multi-user installation on your system:

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

The multi-user installation of Nix will create build users between the user IDs 30001 and 30032, and a group with the group ID 30000. You should run this under your usual user account, not as root. The script will invoke sudo as needed.

Note

If you need Nix to use a different group ID or user ID set, you will have to download the tarball manually and edit the install script.

The installer will modify /etc/bashrc, and /etc/zshrc if they exist. The installer will first back up these files with a .backup-before-nix extension. The installer will also create /etc/profile.d/nix.sh.

Uninstalling

Linux

sudo rm -rf /etc/profile/nix.sh /etc/nix /nix ~root/.nix-profile ~root/.nix-defexpr ~root/.nix-channels ~/.nix-profile ~/.nix-defexpr ~/.nix-channels

# If you are on Linux with systemd, you will need to run:
sudo systemctl stop nix-daemon.socket
sudo systemctl stop nix-daemon.service
sudo systemctl disable nix-daemon.socket
sudo systemctl disable nix-daemon.service
sudo systemctl daemon-reload

There may also be references to Nix in /etc/profile, /etc/bashrc, and /etc/zshrc which you may remove.

macOS

  1. Edit /etc/zshrc and /etc/bashrc to remove the lines sourcing nix-daemon.sh, which should look like this:

    # Nix
    if [ -e '/nix/var/nix/profiles/default/etc/profile.d/nix-daemon.sh' ]; then
      . '/nix/var/nix/profiles/default/etc/profile.d/nix-daemon.sh'
    fi
    # End Nix
    

    If these files haven't been altered since installing Nix you can simply put the backups back in place:

    sudo mv /etc/zshrc.backup-before-nix /etc/zshrc
    sudo mv /etc/bashrc.backup-before-nix /etc/bashrc
    

    This will stop shells from sourcing the file and bringing everything you installed using Nix in scope.

  2. Stop and remove the Nix daemon services:

    sudo launchctl unload /Library/LaunchDaemons/org.nixos.nix-daemon.plist
    sudo rm /Library/LaunchDaemons/org.nixos.nix-daemon.plist
    sudo launchctl unload /Library/LaunchDaemons/org.nixos.darwin-store.plist
    sudo rm /Library/LaunchDaemons/org.nixos.darwin-store.plist
    

    This stops the Nix daemon and prevents it from being started next time you boot the system.

  3. Remove the nixbld group and the _nixbuildN users:

    sudo dscl . -delete /Groups/nixbld
    for u in $(sudo dscl . -list /Users | grep _nixbld); do sudo dscl . -delete /Users/$u; done
    

    This will remove all the build users that no longer serve a purpose.

  4. Edit fstab using sudo vifs to remove the line mounting the Nix Store volume on /nix, which looks like this, LABEL=Nix\040Store /nix apfs rw,nobrowse. This will prevent automatic mounting of the Nix Store volume.

  5. Edit /etc/synthetic.conf to remove the nix line. If this is the only line in the file you can remove it entirely, sudo rm /etc/synthetic.conf. This will prevent the creation of the empty /nix directory to provide a mountpoint for the Nix Store volume.

  6. Remove the files Nix added to your system:

    sudo rm -rf /etc/nix /var/root/.nix-profile /var/root/.nix-defexpr /var/root/.nix-channels ~/.nix-profile ~/.nix-defexpr ~/.nix-channels
    

    This gets rid of any data Nix may have created except for the store which is removed next.

  7. Remove the Nix Store volume:

    sudo diskutil apfs deleteVolume /nix
    

    This will remove the Nix Store volume and everything that was added to the store.

Note

After you complete the steps here, you will still have an empty /nix directory. This is an expected sign of a successful uninstall. The empty /nix directory will disappear the next time you reboot.

You do not have to reboot to finish uninstalling Nix. The uninstall is complete. macOS (Catalina+) directly controls root directories and its read-only root will prevent you from manually deleting the empty /nix mountpoint.

macOS Installation

We believe we have ironed out how to cleanly support the read-only root on modern macOS. New installs will do this automatically, and you can also re-run a new installer to convert your existing setup.

This section previously detailed the situation, options, and trade-offs, but it now only outlines what the installer does. You don't need to know this to run the installer, but it may help if you run into trouble:

  • create a new APFS volume for your Nix store
  • update /etc/synthetic.conf to direct macOS to create a "synthetic" empty root directory to mount your volume
  • specify mount options for the volume in /etc/fstab
    • rw: read-write
    • noauto: prevent the system from auto-mounting the volume (so the LaunchDaemon mentioned below can control mounting it, and to avoid masking problems with that mounting service).
    • nobrowse: prevent the Nix Store volume from showing up on your desktop; also keeps Spotlight from spending resources to index this volume
  • if you have FileVault enabled
    • generate an encryption password
    • put it in your system Keychain
    • use it to encrypt the volume
  • create a system LaunchDaemon to mount this volume early enough in the boot process to avoid problems loading or restoring any programs that need access to your Nix store

Installing a pinned Nix version from a URL

NixOS.org hosts version-specific installation URLs for all Nix versions since 1.11.16, at https://releases.nixos.org/nix/nix-version/install.

These install scripts can be used the same as the main NixOS.org installation script:

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

In the same directory of the install script are sha256 sums, and gpg signature files.

Installing from a binary tarball

You can also download a binary tarball that contains Nix and all its dependencies. (This is what the install script at https://nixos.org/nix/install does automatically.) You should unpack it somewhere (e.g. in /tmp), and then run the script named install inside the binary tarball:

$ cd /tmp
$ tar xfj nix-1.8-x86_64-darwin.tar.bz2
$ cd nix-1.8-x86_64-darwin
$ ./install

If you need to edit the multi-user installation script to use different group ID or a different user ID range, modify the variables set in the file named install-multi-user.