lix/src/nix/flake-update.md

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Examples

• Update all inputs (i.e. recreate the lock file from scratch):

  # nix flake update
  warning: updating lock file '/home/myself/repos/testflake/flake.lock':
  • Updated input 'nix':
      'github:NixOS/nix/9fab14adbc3810d5cc1f88672fde1eee4358405c' (2023-06-28)
    → 'github:NixOS/nix/8927cba62f5afb33b01016d5c4f7f8b7d0adde3c' (2023-07-11)
  • Updated input 'nixpkgs':
      'github:NixOS/nixpkgs/3d2d8f281a27d466fa54b469b5993f7dde198375' (2023-06-30)
    → 'github:NixOS/nixpkgs/a3a3dda3bacf61e8a39258a0ed9c924eeca8e293' (2023-07-05)
  

• Update only a single input:

  # nix flake update nixpkgs
  warning: updating lock file '/home/myself/repos/testflake/flake.lock':
  • Updated input 'nixpkgs':
      'github:NixOS/nixpkgs/3d2d8f281a27d466fa54b469b5993f7dde198375' (2023-06-30)
    → 'github:NixOS/nixpkgs/a3a3dda3bacf61e8a39258a0ed9c924eeca8e293' (2023-07-05)
  

• Update only a single input of a flake in a different directory:

  # nix flake update nixpkgs --flake ~/repos/another
  warning: updating lock file '/home/myself/repos/another/flake.lock':
  • Updated input 'nixpkgs':
      'github:NixOS/nixpkgs/3d2d8f281a27d466fa54b469b5993f7dde198375' (2023-06-30)
    → 'github:NixOS/nixpkgs/a3a3dda3bacf61e8a39258a0ed9c924eeca8e293' (2023-07-05)
  

  Note

  When trying to refer to a flake in a subdirectory, write ./another instead of another. Otherwise Nix will try to look up the flake in the registry.

Description

This command updates the inputs in a lock file (flake.lock). By default, all inputs are updated. If the lock file doesn't exist yet, it will be created. If inputs are not in the lock file yet, they will be added.

Unlike other nix flake commands, nix flake update takes a list of names of inputs to update as its positional arguments and operates on the flake in the current directory. You can pass a different flake-url with --flake to override that default.

The related command nix flake lock also creates lock files and adds missing inputs, but is safer as it will never update inputs already in the lock file.

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