# yui
> 結 — *target-as-truth* dotfiles manager
`yui` is a dotfiles manager that flips the chezmoi flow on its head: edit
your live configs (the **target**), and the source repo updates
automatically. Built to fix three chezmoi pain points:
- having to edit the source first and `apply` afterwards is a constant tax
- apps overwrite the target directly, so source and target drift
- new files apps create aren't tracked, and you can't even notice them
## How it works
The actual files live in your dotfiles repo, and the targets are
**hardlinks / junctions / symlinks** pointing at them. When an app writes
to the target, the link routes the write straight through to source — no
copy step, no drift.
| Linux / macOS | symlink | symlink |
| Windows (default) | hardlink | junction |
| Windows (opt-in) | symlink | symlink (requires Developer Mode / admin) |
Drop a `.yuilink` marker file inside any directory in your source tree
to make `yui` link that whole directory as a single unit — files an
app creates inside it land directly in your source repo.
When an editor's atomic-save breaks a hardlink, `yui` looks at mtimes,
content, and git status to decide between **auto-absorb** (target →
source, with backup), **relink only** (contents identical), or **ask**
(anomaly).
## Install
```sh
cargo install yui-cli
```
Binary lives at `~/.cargo/bin/yui`. Make sure that's on your `PATH`.
## Quick start
```sh
# Initialize a fresh source repo at $DOTFILES (and install git hooks).
yui init --git-hooks
# Edit $DOTFILES/config.toml to declare your mounts, then:
yui apply # render templates + link targets + auto-absorb drift
yui status # show drift across all mounts
yui doctor # diagnose your environment
```
Minimal `$DOTFILES/config.toml`:
```toml
[vars]
git_email = "you@example.com"
[[mount.entry]]
src = "home"
# `~` expands to $HOME on Unix and $USERPROFILE on Windows — use it freely.
dst = "~"
[[mount.entry]]
src = "appdata"
dst = "{{ env(name='APPDATA') }}"
when = "yui.os == 'windows'"
```
`config.local.toml` (gitignored) is for machine-local overrides:
```toml
[vars]
git_email = "you@work.example"
```
Built-in variables exposed to Tera: `yui.os`, `yui.host`, `yui.user`,
`yui.arch`, `yui.source`. Environment variables are read with
`{{ env(name='HOME') }}`. Path values (in `dst`, `--source`, `YUI_SOURCE`,
`.yuilink` `[[link]] dst`, etc.) accept a leading `~` / `~/...` which
expands to `$HOME` (or `$USERPROFILE` on Windows) at apply time —
`dst = "~/.config/foo"` Just Works™ across platforms.
## Status
Pre-release. MVP design complete; implementation in progress.
## License
MIT