NixOS: Difference between revisions

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=== Imperative Operations ===

==== User ~~Environment Management~~ ====

==== User Environments ====

In addition to declarative system configuration, NixOS offers imperative ~~commands~~ to ~~manage ''~~user ~~specific'' package management~~. ~~These operations are managed by the~~ <code>nix-env</code> ~~command line tool~~. ~~The following is a summary of some common operations that can be performed with it:~~

In addition to declarative system configuration, NixOS offers the imperative <code>nix-env</code> command which can be used to install packages at the user level. Packages installed using <code>nix-env</code> are only available to the given user, and do not change system state.

~~''Common <code>nix-env</code> Commands:''~~

{| class="wikitable"

|+ Common <code>nix-env</code> Commands

|-

|Searching for packages

|<code>nix-env -qaP '.*packagename.*'</code>

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==== Channels ====

Nix ''channels'' are mechanisms for distributing Nix expressions ~~alongside~~ the associated binaries for them. Official Nix channels are automatically updated once ~~a certain~~ tests are passed in Nixpkgs' Hydra instance. It is also possible to create one's own Nix channels, but here we focus the official channels. ~~A full list of the available official channels is available at~~ [https://nixos.org/channels/ ~~https://nixos.org/~~channels/]~~, but they can be classified into three main types~~.

Nix ''channels'' are mechanisms for distributing Nix expressions as well as the associated binaries for them; a Nix channel corresponds to a repository in a conventional package management system. Official Nix channels are automatically updated once tests are passed in Nixpkgs' [[Hydra]] instance. It is also possible to create one's own Nix channels, but here we focus the official channels. [https://nixos.org/channels/ A full list of the available official channels is available].

''~~Channel Types:~~''

NixOS is distributed through a number of channels. These NixOS channels can be broadly categorised into ''stable'' and ''unstable'' channels, and ''large'' and ''small'' channels:

~~{| class="wikitable"~~

|Stable

* Stable/unstable:

~~|''~~nixos-17.09''

** Stable channels (<code>nixos-17.09</code>) provide conservative updates for fixing bugs and security vulnerabilities, but do not receive major updates after initial release. New stable channels are released every six months.

~~|These receive~~ conservative updates for fixing bugs and security vulnerabilities.

** Unstable channels (<code>nixos-unstable</code>, <code>nixos-unstable-small</code>) correspond to the main development branch of Nixpkgs, delivering the latest tested updates on a rolling basis.

|-

* Large/small:

~~|Unstable~~

** Large channels (<code>nixos-17.09</code>, <code>nixos-unstable</code>) provide binary builds for the full breadth of Nixpkgs.

~~|''~~nixos-unstable''

** Small channels (<code>nixos-17.09-small</code>, <code>nixos-unstable-small</code>) are identical to large channels, but contain fewer binaries. This means they update faster, but require more to be built from source.

~~| Corresponds~~ to the main development branch of Nixpkgs, delivering the latest tested updates.

|-

Most users will want the stable/large channel, currently <code>nixos-17.09</code>.

|Small

~~|''~~nixos-17.09-small'', ''nixos-unstable-small''

~~| Identical~~ to ~~their normal namesakes~~, but ~~containing~~ fewer binaries. This means they update faster but require more to be built from source.

|}

NixOS ~~will use~~ the root~~'s channels~~ to update the system wide configuration~~, and user-specific~~ channels ~~to manage~~ the user environment~~; this means~~ that you ~~must~~ <code>~~sudo~~</code> ~~commands intended to manage~~ the ~~channel your~~ <code>~~configuration.~~nix</code> ~~should use. The following are common commands to manage channels on NixOS~~:

Like packages installed via <code>nix-env</code>, channels are managed at user-level. NixOS uses the channels set for the <code>root</code> user to update the system-wide configuration; channels set for other users control only the user environment for that user. If you wish to change the channel used by the system-level configuration (<code>/etc/nixos/configuration.nix</code>), ensure you run the correct <code>nix-channel</code> command as root:

{| class="wikitable"

|+ Common nix-channel commands

|-

|Listing current channels

|<code>nix-channel --list</code>

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|}

Note that ~~after~~ updating channels~~, one still has~~ to rebuild ~~with <code>nixos-rebuild switch</code>~~, ~~but one~~ can ~~also~~ run <code>nixos-rebuild ~~switch~~ --upgrade</code> to ~~update channels and rebuild~~.

Note that updating channels won't cause a rebuild in itself; if you want to update channels and rebuild, you can run <code>nixos rebuild --upgrade</code> to do both in one step.

== Internals ==

@@ Line 94: / Line 94: @@
 === Imperative Operations ===
-====  User Environment Management ====
+====  User Environments ====
-In addition to declarative system configuration, NixOS offers imperative commands to manage ''user specific'' package management. These operations are managed by the <code>nix-env</code> command line tool. The following is a summary of some common operations that can be performed with it:
+In addition to declarative system configuration, NixOS offers the imperative <code>nix-env</code> command which can be used to install packages at the user level. Packages installed using <code>nix-env</code> are only available to the given user, and do not change system state.
-''Common <code>nix-env</code> Commands:''
 {|  class="wikitable"
+|+ Common <code>nix-env</code> Commands
+|-
 |Searching for packages
 |<code>nix-env -qaP '.*packagename.*'</code>
@@ Line 118: / Line 119: @@
 ==== Channels ====
-Nix ''channels'' are mechanisms for distributing Nix expressions alongside the associated binaries for them. Official Nix channels are automatically updated once a certain tests are passed in Nixpkgs' Hydra instance. It is also possible to create one's own Nix channels, but here we focus the official channels. A full list of the available official channels is available at [https://nixos.org/channels/ https://nixos.org/channels/], but they can be classified into three main types.
+Nix ''channels'' are mechanisms for distributing Nix expressions as well as the associated binaries for them; a Nix channel corresponds to a repository in a conventional package management system. Official Nix channels are automatically updated once tests are passed in Nixpkgs' [[Hydra]] instance. It is also possible to create one's own Nix channels, but here we focus the official channels. [https://nixos.org/channels/ A full list of the available official channels is available].
-''Channel Types:''
+NixOS is distributed through a number of channels. These NixOS channels can be broadly categorised into ''stable'' and ''unstable'' channels, and ''large'' and ''small'' channels:
-{|  class="wikitable"
-|Stable
+* Stable/unstable:
-|''nixos-17.09''
+** Stable channels (<code>nixos-17.09</code>) provide conservative updates for fixing bugs and security vulnerabilities, but do not receive major updates after initial release. New stable channels are released every six months.
-|These receive conservative updates for fixing bugs and security vulnerabilities.
+** Unstable channels (<code>nixos-unstable</code>, <code>nixos-unstable-small</code>) correspond to the main development branch of Nixpkgs, delivering the latest tested updates on a rolling basis.
-|-
+* Large/small:
-|Unstable
+** Large channels (<code>nixos-17.09</code>, <code>nixos-unstable</code>) provide binary builds for the full breadth of Nixpkgs.
-|''nixos-unstable''
+** Small channels (<code>nixos-17.09-small</code>, <code>nixos-unstable-small</code>) are identical to large channels, but contain fewer binaries. This means they update faster, but require more to be built from source.
-| Corresponds to the main development branch of Nixpkgs, delivering the latest tested updates.
-|-
+Most users will want the stable/large channel, currently <code>nixos-17.09</code>.
-|Small
-|''nixos-17.09-small'', ''nixos-unstable-small''
-| Identical to their normal namesakes, but containing fewer binaries. This means they update faster but require more to be built from source.
-|}
-NixOS will use the root's channels to update the system wide configuration, and user-specific channels to manage the user environment; this means that you must <code>sudo</code> commands intended to manage the channel your <code>configuration.nix</code> should use. The following are common commands to manage channels on NixOS:
+Like packages installed via <code>nix-env</code>, channels are managed at user-level. NixOS uses the channels set for the <code>root</code> user to update the system-wide configuration; channels set for other users control only the user environment for that user. If you wish to change the channel used by the system-level configuration (<code>/etc/nixos/configuration.nix</code>), ensure you run the correct <code>nix-channel</code> command as root:
-{|  class="wikitable"
+{| class="wikitable"
+|+ Common nix-channel commands
+|-
 |Listing current channels
 |<code>nix-channel --list</code>
@@ Line 157: / Line 156: @@
 |}
-Note that after updating channels, one still has to rebuild with <code>nixos-rebuild switch</code>, but one can also run <code>nixos-rebuild switch --upgrade</code> to update channels and rebuild.
+Note that updating channels won't cause a rebuild in itself; if you want to update channels and rebuild, you can run <code>nixos rebuild --upgrade</code> to do both in one step.
 == Internals ==