# Getting Started

Arc is a delta-based version control system written in Rust. It builds exclusively through Nix.

## Building

Arc uses a Nix flake (nixpkgs-unstable, flake-parts, fenix, crane):

```sh
nix build
```

Enter a dev shell with `nix develop` (provides rustc, cargo, clippy, rustfmt, git, pkg-config, cmake, perl).

Run Arc with `nix run` or `result/bin/arc` after building.

## Configuration

```sh
arc config set user.name "yourname"
arc config set user.email "you@example.com"
```

Global config lives at `$XDG_CONFIG_HOME/arc/config.yml` (or `~/.config/arc/config.yml`).

## Creating a Repository

```sh
arc init [path]
```

This creates a `.arc/` directory containing:

- `commits/` — commit storage
- `bookmarks/` — branches (default: `main`)
- `tags/` — tagged commits
- `stashes/` — stashed changes
- `config.yml` — repository config
- `HEAD` — current position

The default remote is `origin`.

## Tracking Changes

Arc tracks changes automatically — there is no staging area.

```sh
arc status          # see what changed
arc commit <message> # commit all changes
arc log             # view history
arc diff            # see diffs
```

## Ignoring Files

Create a `.arcignore` or `.ignore` file with gitignore-like glob syntax. Prefix a pattern with `!` to negate it.

## Working with Git Repositories

Clone a git repo:

```sh
arc clone <url> [path]
```

Migrate an existing git repo (run inside the repo):

```sh
arc migrate
```