nix-env can read priorities from a derivations meta attributes, but this
only works when installing a nix expression.
nix-env can also install bare store paths, however meta attributes are
not readable in that case. This means that a store path can not be
installed with a specific priority.
Some cases where it is advantageous to install a store path: a remote
host following a `nix copy`, or any time you want to save some
evaluation time and happen to already know the store path.
This PR addresses this shortcoming by adding a --priority flag to
nix-env --install.
The current instructions for building the Nix manual include a command that doesn't work as described. Specifically:
```
nix build .#nix^doc
```
Running this command results in the error:
```
error: derivation '/nix/store/hddqxzfqgx2fhj8q66ss3idym7pk7aj1-nix-2.26.0pre20250107_383ab87.drv' does not have wanted outputs 'doc'
```
However, this command works if you specify the Nix version explicitly, such as:
```
nix build nix/2.24.11#nix^doc
```
Additionally, these commands are run within the Nix root directory.
However, the nix build .#nix^doc command does work when run from the nixpkgs directory and generates the NixOS manual.
I'm not sure if I'm missing something. Is the `nix^doc` supposed to be added somehow to flake outputs?
The incremental build section does not work since as make has been decommissioned in favor of Meson. Should this be simply deleted?
The experimental `nix eval` command already supports a `--raw` flag.
This commit implements the same flag for the stable nix-instantiate command.
Until now instructions and scripts that didn't want to rely on experimental
features had to use workarounds such as:
nix-instantiate --eval <something> | tr -d \"
(which also undesirably also removes double quotation marks within the string), or
nix-instantiate --eval <something> | jq -j
(which undesirably depends on another package).
Co-authored-by: Silvan Mosberger <silvan.mosberger@tweag.io>
When resolving indirect flake references like `nixpkgs` in `flake.nix`
files, Nix will no longer use the system and user flake registries. It
will only use the global flake registry and overrides given on the
command line via `--override-flake`.
