# Fnug

> [!WARNING]
> The main branch is currently undergoing a refactor to Rust. If you're looking for the latest Python version, see the [`python`](https://github.com/nickolaj-jepsen/fnug/tree/python) branch.

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[![Crates.io](https://img.shields.io/crates/v/fnug)](https://crates.io/crates/fnug)
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Fnug is a TUI command runner that automatically selects and executes lint and test commands based on git changes or file watching. Think of it as a terminal multiplexer (like [tmux](https://github.com/tmux/tmux/wiki)), but purpose-built for running your dev commands side by side.

![Fnug demo](docs/demo.gif)

## Features

- **Git integration** — automatically select commands based on uncommitted file changes
- **File watching** — monitor the file system and re-select commands when files change
- **Terminal emulation with scrollback** — full PTY support for interactive commands and long output
- **Headless mode** (`fnug check`) — run selected commands without the TUI, useful for CI
- **Git hook integration** (`fnug init-hooks`) — install a pre-commit hook that runs `fnug check`
- **Command dependencies** — define `depends_on` to control execution order
- **Environment variables** — set per-command or per-group env vars
- **Nested command groups** — organize commands into a hierarchical tree with inherited settings
- **Workspace support** — discover and merge `.fnug.yaml` files from subdirectories in mono-repos

## Installation

### From crates.io

```bash
cargo install fnug
```

### From PyPI

```bash
# With uv
uv tool install fnug

# With pipx
pipx install fnug
```

### From GitHub Releases

Download a prebuilt binary from [GitHub Releases](https://github.com/nickolaj-jepsen/fnug/releases).

### With Nix

```bash
# Run directly
nix run github:nickolaj-jepsen/fnug

# Or install to profile
nix profile install github:nickolaj-jepsen/fnug
```

### From source

```bash
git clone https://github.com/nickolaj-jepsen/fnug.git
cd fnug
cargo install --path .
```

## Usage

Run `fnug` in a directory with a `.fnug.yaml` configuration file (or pass `-c path/to/config.yaml`).

### Subcommands

| Command           | Description                                                     |
| ----------------- | --------------------------------------------------------------- |
| `fnug`            | Launch the TUI                                                  |
| `fnug check`      | Run selected commands headlessly (exit code reflects pass/fail) |
| `fnug init-hooks` | Install a git pre-commit hook that runs `fnug check`            |

### Flags

| Flag              | Description                                                     |
| ----------------- | --------------------------------------------------------------- |
| `-c <path>`       | Path to config file                                             |
| `--no-workspace`  | Disable workspace resolution (don't search for a parent root)   |
| `--log-file`      | Write logs to a file                                            |
| `--log-level`     | Log level: off, error, warn, info, debug, trace (default: info) |
| `--fail-fast`     | Stop on first failure (`check` only)                            |
| `--no-tui`        | Never prompt to open TUI on failure (`check` only)              |
| `--mute-success`  | Suppress output for passing commands (`check` only)             |
| `--all`           | Include commands with `auto.check: false` (`check` only)        |
| `--force`         | Overwrite existing hook (`init-hooks` only)                     |

## Configuration

Fnug searches for `.fnug.yaml`, `.fnug.yml`, or `.fnug.json` from the current directory upward.

### Minimal example

```yaml
fnug_version: 0.1.0
name: my-project
commands:
  - name: hello
    cmd: echo world
```

### Git auto-selection

Select commands based on uncommitted changes. Re-trigger with `g` in the TUI.

```yaml
fnug_version: 0.1.0
name: my-project
commands:
  - name: lint
    cmd: cargo clippy
    auto:
      git: true
      path:
        - "./src"
      regex:
        - "\\.rs$"
```

### File watching

Monitor the file system and select commands when matching files change. Can be combined with git auto.

```yaml
fnug_version: 0.1.0
name: my-project
commands:
  - name: test
    cmd: cargo test
    auto:
      watch: true
      path:
        - "./src"
      regex:
        - "\\.rs$"
```

### Always auto-selection

Mark commands that should always be selected, regardless of git changes or file watching.

```yaml
fnug_version: 0.1.0
name: my-project
commands:
  - name: typecheck
    cmd: cargo check
    auto:
      always: true
```

### Excluding commands from check mode

Commands with `auto.check: false` are skipped during `fnug check` (and git hooks) but remain auto-selected in the TUI. Use `fnug check --all` to include them.

Useful for commands that are too slow or noisy for pre-commit checks but you still want to run them automatically in the TUI.

```yaml
fnug_version: 0.1.0
name: my-project
commands:
  - name: unit tests
    cmd: cargo test
    auto:
      git: true
  - name: integration tests
    cmd: cargo test --release
    auto:
      git: true
      check: false   # skip in `fnug check`, still auto-selected in TUI
```

### Nested groups with inheritance

Groups inherit `cwd`, `auto`, and `env` settings from their parent.

```yaml
fnug_version: 0.1.0
name: my-project
children:
  - name: backend
    auto:
      git: true
      watch: true
      path:
        - "./src"
      regex:
        - "\\.rs$"
    commands:
      - name: fmt
        cmd: cargo fmt
      - name: test
        cmd: cargo test
      - name: clippy
        cmd: cargo clippy
```

### Workspace

Workspace mode discovers `.fnug.yaml` files in subdirectories and merges them as child groups. This is useful for mono-repos where each package has its own config.

When `workspace: true`, fnug walks the filesystem (skipping `.gitignore`'d and hidden directories) to find sub-configs. Files do not need to be git-tracked to be discovered.

```yaml
# Auto-discover sub-configs (walks up to 5 levels deep)
fnug_version: 0.1.0
name: my-monorepo
workspace: true
commands:
  - name: root-lint
    cmd: echo "root"
```

```yaml
# Custom max scan depth
workspace:
  max_depth: 2
```

```yaml
# Explicit glob patterns
workspace:
  paths:
    - "./packages/*/"
    - "./apps/*/"
```

When run from a subdirectory that contains a `.fnug.yaml`, fnug automatically resolves upward to the nearest workspace root. Use `--no-workspace` to disable this behavior.

### Advanced example

See this project's [`.fnug.yaml`](.fnug.yaml) for a full example.

### Configuration reference

#### Root fields

| Field          | Type              | Description                                                       |
| -------------- | ----------------- | ----------------------------------------------------------------- |
| `fnug_version` | string            | Expected fnug version — warns on mismatch                         |
| `name`         | string            | Display name for the root group                                   |
| `workspace`    | bool / object     | Enable workspace mode (see [Workspace](#workspace))               |
| `commands`     | list              | Top-level commands                                                |
| `children`     | list              | Nested command groups                                             |
| `cwd`          | string            | Working directory (inherited by children)                         |
| `env`          | map               | Environment variables (inherited by children)                     |
| `auto`         | object            | Default auto rules (inherited by children)                        |

#### Command fields

| Field        | Type              | Description                                                         |
| ------------ | ----------------- | ------------------------------------------------------------------- |
| `name`       | string            | Display name (required)                                             |
| `cmd`        | string            | Shell command to run (required)                                     |
| `id`         | string            | Custom identifier — defaults to the command name                    |
| `cwd`        | string            | Working directory override                                          |
| `env`        | map               | Extra environment variables                                         |
| `auto`       | object            | Auto-selection rules (see below)                                    |
| `depends_on` | list of strings   | Command IDs that must finish before this one runs                   |
| `scrollback` | integer           | PTY scrollback buffer size (number of lines)                        |

#### Group fields

| Field      | Type              | Description                                                           |
| ---------- | ----------------- | --------------------------------------------------------------------- |
| `name`     | string            | Display name (required)                                               |
| `id`       | string            | Custom identifier — defaults to the group name                        |
| `cwd`      | string            | Working directory (inherited by children)                             |
| `env`      | map               | Environment variables (inherited by children)                         |
| `auto`     | object            | Default auto rules (inherited by children)                            |
| `commands` | list              | Commands in this group                                                |
| `children` | list              | Nested child groups                                                   |

#### Auto fields

| Field    | Type              | Description                                                             |
| -------- | ----------------- | ----------------------------------------------------------------------- |
| `git`    | bool              | Select when git-changed files match `path`/`regex`                      |
| `watch`  | bool              | Select when watched files match `path`/`regex`                          |
| `always` | bool              | Always selected regardless of changes                                   |
| `path`   | list of strings   | Path prefixes to match against (e.g. `"./src"`)                        |
| `regex`  | list of strings   | Regex patterns to match against file paths (e.g. `"\\.rs$"`)           |
| `check`  | bool              | Include in `fnug check` — set `false` to skip (default `true`)         |

## Keyboard Shortcuts

| Key       | Context  | Action                            |
| --------- | -------- | --------------------------------- |
| `j` / `↓` | Tree     | Move down                         |
| `k` / `↑` | Tree     | Move up                           |
| `h` / `←` | Tree     | Collapse group / Deselect command |
| `l` / `→` | Tree     | Expand group / Select command     |
| `Space`   | Tree     | Toggle expand/select              |
| `Enter`   | Tree     | Run all selected commands         |
| `r`       | Tree     | Run current command               |
| `s`       | Tree     | Stop current command              |
| `c`       | Tree     | Clear current command             |
| `g`       | Tree     | Git auto-select                   |
| `/`       | Tree     | Search/filter commands            |
| `Esc`     | Search   | Clear search                      |
| `L`       | Tree     | Toggle log panel                  |
| `Tab`     | Tree     | Focus terminal                    |
| `Esc`     | Terminal | Back to tree                      |
| `Ctrl+R`  | Global   | Toggle fullscreen                 |
| `Ctrl+C`  | Global   | Quit                              |
| `q`       | Tree     | Quit                              |

### Mouse

- **Click** a tree item to select it
- **Double-click** a command to run it, or a group to expand/collapse
- **Click** the selection orb (●/○) or arrow (▼/▶) to toggle
- **Drag** the separator between tree and terminal to resize
- **Scroll wheel** in the terminal panel to scroll output
- **Right-click** a command for a context menu with run/stop/clear options
