R""(

# Examples

* Upgrade Nix to the stable version declared in Nixpkgs:

  ```console
  # nix upgrade-nix
  ```

* Upgrade Nix in a specific profile:

  ```console
  # nix upgrade-nix --profile ~alice/.local/state/nix/profiles/profile
  ```

# Description

This command upgrades Nix to the stable version.

By default, the latest stable version is defined by Nixpkgs, in
[nix-fallback-paths.nix](https://github.com/NixOS/nixpkgs/raw/master/nixos/modules/installer/tools/nix-fallback-paths.nix)
and updated manually. It may not always be the latest tagged release.

By default, it locates the directory containing the `nix` binary in the `$PATH`
environment variable. If that directory is a Nix profile, it will
upgrade the `nix` package in that profile to the latest stable binary
release.

You cannot use this command to upgrade Nix in the system profile of a
NixOS system (that is, if `nix` is found in `/run/current-system`).

)""