diff options
Diffstat (limited to 'src/nix/profile.md')
| -rw-r--r-- | src/nix/profile.md | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/src/nix/profile.md b/src/nix/profile.md new file mode 100644 index 000000000..d3ddcd3d1 --- /dev/null +++ b/src/nix/profile.md @@ -0,0 +1,107 @@ +R""( + +# Description + +`nix profile` allows you to create and manage *Nix profiles*. A Nix +profile is a set of packages that can be installed and upgraded +independently from each other. Nix profiles are versioned, allowing +them to be rolled back easily. + +# Default profile + +The default profile used by `nix profile` is `$HOME/.nix-profile`, +which, if it does not exist, is created as a symlink to +`/nix/var/nix/profiles/per-user/default` if Nix is invoked by the +`root` user, or `/nix/var/nix/profiles/per-user/`*username* otherwise. + +You can specify another profile location using `--profile` *path*. + +# Filesystem layout + +Profiles are versioned as follows. When using profile *path*, *path* +is a symlink to *path*`-`*N*, where *N* is the current *version* of +the profile. In turn, *path*`-`*N* is a symlink to a path in the Nix +store. For example: + +```console +$ ls -l /nix/var/nix/profiles/per-user/alice/profile* +lrwxrwxrwx 1 alice users 14 Nov 25 14:35 /nix/var/nix/profiles/per-user/alice/profile -> profile-7-link +lrwxrwxrwx 1 alice users 51 Oct 28 16:18 /nix/var/nix/profiles/per-user/alice/profile-5-link -> /nix/store/q69xad13ghpf7ir87h0b2gd28lafjj1j-profile +lrwxrwxrwx 1 alice users 51 Oct 29 13:20 /nix/var/nix/profiles/per-user/alice/profile-6-link -> /nix/store/6bvhpysd7vwz7k3b0pndn7ifi5xr32dg-profile +lrwxrwxrwx 1 alice users 51 Nov 25 14:35 /nix/var/nix/profiles/per-user/alice/profile-7-link -> /nix/store/mp0x6xnsg0b8qhswy6riqvimai4gm677-profile +``` + +Each of these symlinks is a root for the Nix garbage collector. + +The contents of the store path corresponding to each version of the +profile is a tree of symlinks to the files of the installed packages, +e.g. + +```console +$ ll -R /nix/var/nix/profiles/per-user/eelco/profile-7-link/ +/nix/var/nix/profiles/per-user/eelco/profile-7-link/: +total 20 +dr-xr-xr-x 2 root root 4096 Jan 1 1970 bin +-r--r--r-- 2 root root 1402 Jan 1 1970 manifest.json +dr-xr-xr-x 4 root root 4096 Jan 1 1970 share + +/nix/var/nix/profiles/per-user/eelco/profile-7-link/bin: +total 20 +lrwxrwxrwx 5 root root 79 Jan 1 1970 chromium -> /nix/store/ijm5k0zqisvkdwjkc77mb9qzb35xfi4m-chromium-86.0.4240.111/bin/chromium +lrwxrwxrwx 7 root root 87 Jan 1 1970 spotify -> /nix/store/w9182874m1bl56smps3m5zjj36jhp3rn-spotify-1.1.26.501.gbe11e53b-15/bin/spotify +lrwxrwxrwx 3 root root 79 Jan 1 1970 zoom-us -> /nix/store/wbhg2ga8f3h87s9h5k0slxk0m81m4cxl-zoom-us-5.3.469451.0927/bin/zoom-us + +/nix/var/nix/profiles/per-user/eelco/profile-7-link/share/applications: +total 12 +lrwxrwxrwx 4 root root 120 Jan 1 1970 chromium-browser.desktop -> /nix/store/4cf803y4vzfm3gyk3vzhzb2327v0kl8a-chromium-unwrapped-86.0.4240.111/share/applications/chromium-browser.desktop +lrwxrwxrwx 7 root root 110 Jan 1 1970 spotify.desktop -> /nix/store/w9182874m1bl56smps3m5zjj36jhp3rn-spotify-1.1.26.501.gbe11e53b-15/share/applications/spotify.desktop +lrwxrwxrwx 3 root root 107 Jan 1 1970 us.zoom.Zoom.desktop -> /nix/store/wbhg2ga8f3h87s9h5k0slxk0m81m4cxl-zoom-us-5.3.469451.0927/share/applications/us.zoom.Zoom.desktop + +… +``` + +The file `manifest.json` records the provenance of the packages that +are installed in this version of the profile. It looks like this: + +```json +{ + "version": 1, + "elements": [ + { + "active": true, + "attrPath": "legacyPackages.x86_64-linux.zoom-us", + "originalUri": "flake:nixpkgs", + "storePaths": [ + "/nix/store/wbhg2ga8f3h87s9h5k0slxk0m81m4cxl-zoom-us-5.3.469451.0927" + ], + "uri": "github:NixOS/nixpkgs/13d0c311e3ae923a00f734b43fd1d35b47d8943a" + }, + … + ] +} +``` + +Each object in the array `elements` denotes an installed package and +has the following fields: + +* `originalUri`: The [flake reference](./nix3-flake.md) specified by + the user at the time of installation (e.g. `nixpkgs`). This is also + the flake reference that will be used by `nix profile upgrade`. + +* `uri`: The immutable flake reference to which `originalUri` + resolved. + +* `attrPath`: The flake output attribute that provided this + package. Note that this is not necessarily the attribute that the + user specified, but the one resulting from applying the default + attribute paths and prefixes; for instance, `hello` might resolve to + `packages.x86_64-linux.hello` and the empty string to + `defaultPackage.x86_64-linux`. + +* `storePath`: The paths in the Nix store containing the package. + +* `active`: Whether the profile contains symlinks to the files of this + package. If set to false, the package is kept in the Nix store, but + is not "visible" in the profile's symlink tree. + +)"" |