fff.cr — Fucking Fast File Manager

A terminal-based file manager written in Crystal. Ported from the original Bash version for performance, safety, and maintainability.

Features

• Fast: LS_COLORS caching, optimized incremental render loop, no flicker
• Modern Themes: Truecolor RGB central theme system with 5 built-in presets (default, catppuccin-mocha, gruvbox-dark, nord, dracula).
• Selection Indicator: Sleek vertical block (▌) selection marker keeping native file type colors bolded on selection background.
• Pill-Shaped Badges: Status and top bar indicators (clipboard, marks, sorting, git, file/folder counts, and directory size) rendered in colored pill badges.
• Nerd Font Icons: Support for file and directory icons using Nerd Fonts (over 100+ extensions and 35+ special file mapping).
• Dual-Pane View (Preview Panel): Interactive directory and file content preview side panel (automatically adapts when terminal columns >= 80).
• Details Columns: Shows file size and modification time directly in the file list, including on the selected line.
• Empty Directory State: Centered placeholder display for empty folders.
• Toast Notifications: Interactive notification system (Error, Success, Warning, Info) with custom colors and icons, featuring auto-expiry.
• Navigable Search: Fuzzy filename filtering, ripgrep content search (! prefix), and recursive directory tree search (> prefix) while keeping cursor navigation live.
• Progress Bars: Interactive progress bar for bulk operations (copying/deleting 5+ files).
• Inline Prompts & Confirms: Inputs (new file, new dir, rename, go-to-dir) and confirmations (delete, executable toggle) stay inside the TUI.
• File Operations: Copy, move, delete (trash), rename, bulk rename, symlink with auto-advance navigation.
• Smart Full Preview: Full-screen preview via bat → less → built-in fallback chain; file attributes via File::Info/stat
• Picker Mode: -p flag writes selection to ~/.cache/fff/opened_file for external tool integration
• Secure: All external commands via Process.run (no shell injection), pre-operation writability checks
• Customizable: Full keybinding, theme, and layout control via environment variables or ~/.config/fff/config.json

Installation

Requirements

• Crystal 1.20.1+
• Windows 11, Linux, or macOS terminal (with true-color support recommended)

System dependencies

Platform	Package	Notes
Debian/Ubuntu	libreadline-dev	Crystal links against readline on Linux
Fedora/RHEL	readline-devel	Same as above
Arch	readline	Included in base
macOS	(built-in)	Comes with Xcode Command Line Tools
Windows 11	(none)	Crystal uses Win32 console API

make deps installs Crystal shards and auto-patches known crystal-term bugs.

Build

On Linux/macOS:

make deps       # install shards
make build      # release build → bin/fff-cr
make debug      # debug build (faster compile)
make run        # build + run
make test       # run test suite

# Optional: system-wide install (including man page)
sudo make install

On Windows 11 (PowerShell):

shards install                              # install shards
crystal run scripts/patch_shards.cr         # patch known shard bug (ESC hang)
crystal build src/fff.cr -o bin/fff-cr.exe  # build fff-cr.exe
crystal spec spec/fff/                      # run unit tests
.\bin\fff-cr.exe                            # run the app

Usage

fff-cr                    # open current directory
fff-cr /path/to/dir       # open specific directory
fff-cr -p                 # picker mode (writes to opened_file cache)

Key Bindings

Key	Action	Key	Action
j/k	Down/Up	l/h	Enter/Parent
q	Quit	?	Help overlay
/	Search (Navigable)	space	Mark
m	Mark all	y/v	Copy/Cut
p	Paste	d	Delete (trash)
t	Go to trash	n	New dir
f	New file	r	Rename
b	Bulk rename	i	Preview
x	Attributes	X	Toggle executable
s	Spawn shell	g/G	Top/Bottom
↑/↓	Cursor	PgUp/PgDn	Page up/down
.	Toggle hidden	~	Home
-	Previous dir	e	Refresh
= / +	Cycle sort / Reverse	:	Go to dir
S	Symlink	1-9	Favorites

In search and rename modes, ←/→ move within the input text, Backspace/Delete edit, Home/End jump to start/end. In normal mode, ESC clears active search filters and marks. In search mode, ESC cancels the search; if you navigated the results with arrow keys, it drops you directly onto the selected file, otherwise it reverts to your pre-search position.

All bindings are configurable via FFF_KEY_* environment variables.

Search Engine Prefixes

When in search mode (triggered by /), you can prefix your query to activate different search modes:

Prefix	Mode	Description
(none)	Fuzzy Filename	Fuzzy matches filenames within the current directory.
!	Content Search	Calls rg (ripgrep) to search file content (requires pressing Enter to search).
>	Recursive Search	Recursively fuzzy searches files in the directory tree (up to 5 levels deep, capped at 200 results) (requires pressing Enter to search).

Configuration

fff reads from environment variables first, then falls back to ~/.config/fff/config.json.

UI & Layout Settings

Env Variable	Config JSON Key	Description / Values
FFF_THEME	theme.name	UI Theme: default, catppuccin-mocha, gruvbox-dark, nord, dracula (Default: default)
FFF_ICONS	icons	Enable Nerd Font icons: 1 or true (Default: disabled)
FFF_COLUMNS	columns	Show details columns (size/date): 0 to hide (Default: enabled)
FFF_COLUMN_MODE	column_mode	Column display mode: size, date, or both (Default: both)
FFF_PREVIEW	preview	Enable directory/file preview side-panel when term is wide enough: 1 or true (Default: disabled)
FFF_PREVIEW_WIDTH	preview_width	Preview panel width: "40%" (ratio), "30" (absolute columns), nil → default 40% capped at 50

Key variables

export FFF_OPENER="xdg-open"              # file opener
export FFF_FAV1="$HOME/Documents"         # favorite dirs 1-9
export FFF_CD_ON_EXIT="1"                 # save cwd on exit
export FFF_TRASH="$HOME/.local/share/fff/trash"

# Example UI settings:
export FFF_THEME="catppuccin-mocha"
export FFF_ICONS="1"
export FFF_PREVIEW="1"
export FFF_PREVIEW_WIDTH="40%"

Full list of FFF_KEY_* variables: UP, DOWN, ENTER, QUIT, SEARCH, PARENT, MARK, MARK_ALL, COPY, MOVE, PASTE, DELETE, NEW_DIR, MKFILE, RENAME, BULK_RENAME, PREVIEW, SHELL, HIDDEN, HOME, PREVIOUS, REFRESH, ATTRIBUTES, EXECUTABLE, GO_DIR, GO_TRASH, SYMLINK, TOP, BOTTOM, PAGE_UP, PAGE_DOWN.

{
  "editor": "vim",
  "opener": "xdg-open",
  "trash_dir": "/path/to/trash",
  "theme": { "name": "catppuccin-mocha" },
  "icons": true,
  "columns": true,
  "column_mode": "both",
  "preview": true,
  "preview_width": "40%",
  "favorites": { "1": "/home/user/Documents" },
  "keys": { "up": "k", "down": "j" },
  "bookmarks": { "proj": "/home/user/projects" }
}

Preview

Press i to preview a file. The preview chain tries:

1. bat --paging=always — syntax-highlighted, scrollable
2. less — paged, searchable
3. Built-in — plain text with full scroll support

Directories always use the built-in preview.

Project Structure

.
├── bin/fff-cr               # compiled binary
├── man/fff-cr.1             # man page
├── src/
│   ├── fff.cr               # entry point
│   └── fff/
│       ├── config.cr
│       ├── directory_manager.cr
│       ├── draw_state.cr
│       ├── file_manager.cr
│       ├── file_op_handlers.cr
│       ├── file_operations.cr
│       ├── file_service.cr
│       ├── format_utils.cr
│       ├── icon_provider.cr
│       ├── input_mode.cr
│       ├── message_bus.cr
│       ├── navigation_handlers.cr
│       ├── preview_panel.cr
│       ├── progress_bar.cr
│       ├── search_engine.cr
│       ├── terminal.cr
│       ├── theme.cr
│       ├── ui_renderer.cr
│       └── view_handlers.cr
├── spec/                    # test suite
│   ├── spec_helper.cr
│   ├── fff/
│   └── integration/
├── Makefile
├── shard.yml
├── .ameba.yml               # linter config
└── LICENSE

Architecture

• FFF::Application — CLI argument parsing, terminal setup
• FFF::Config — env var & JSON config management, LS_COLORS parsing, layout preferences
• FFF::DirectoryManager — directory reading, sorting, hidden-file filtering
• FFF::DrawState — bundles all redraw parameters into one struct
• FFF::FileManager — event loop, hash-table key dispatch, and TUI router; includes NavigationHandlers, FileOpHandlers, ViewHandlers
• FFF::FileOperations — file/directory creation, deletion, copying with callback blocks for progress tracking
• FFF::FileService — low-level copy/move/trash/symlink with writability checks
• FFF::FormatUtils — shared helpers (human_size, date formatting), FFF::HOME constant
• FFF::IconProvider — maps file extensions and special names to Nerd Font icons
• FFF::InputMode — search/rename text input with cursor control, editing, and search mode matching
• FFF::MessageBus — thread-safe TUI toast notification queue (Error/Success/Warning/Info)
• FFF::PreviewPanel — split pane displaying file previews/details and directory entries
• FFF::ProgressBar — ANSI progress bar tracking bulk operations
• FFF::SearchEngine — fuzzy filename matching, ripgrep content search, and recursive tree search
• FFF::Terminal — crystal-term shard wrapper
• FFF::Theme — truecolor RGB color palette system with pre-configured styles
• FFF::UIRenderer — incremental, flicker-free drawing, truecolor CSS/TUI styling, layout composition

Development

make test       # run all specs
make format     # crystal tool format
make lint       # ameba static analysis

Running Tests

make test           # all specs (298 examples)
crystal spec spec/integration/navigation_integration_spec.cr
crystal spec spec/integration/file_operations_integration_spec.cr
crystal spec spec/integration/ui_integration_spec.cr

Test Architecture

• 246 unit tests across 16 spec files (config, directory_manager, draw_state, file_operations, file_op_handlers, file_service, format_utils, icon_provider, input_mode, message_bus, navigation_handlers, preview_panel, progress_bar, search_engine, theme, ui_renderer)

• 52 integration tests across 4 suites (navigation, file_operations, ui, advanced) — use MockTerminal to simulate keyboard input and prompts without a real TTY

• Both specs run headless; no terminal or display required

Patches

The project patches one remaining crystal-term shard bug (the term-reader ESC hang) via scripts/patch_shards.cr after shards install. make deps applies it automatically on Linux/macOS; on Windows, run crystal run scripts/patch_shards.cr manually. The script is idempotent. See AGENTS.md for details.

License

MIT. See LICENSE.