Janus

English · Русский

A fast two-panel file manager for the terminal, written in Rust. Named after Janus, the two-faced Roman god who looks both ways at once — like its two panels. Two panels, a preview with syntax highlighting, a built-in editor, recursive search, archives, a "largest objects" view, git status and a drive picker — all from the keyboard, with every long operation running in the background.

Contents

• Features at a glance
• Installation
• Panels and navigation
• Preview
• Editor
• Search
• Copy, move, delete
• Rename
• Archives
• Largest objects
• Drives and volumes
• Help, hints and settings
• Themes
• Command line
• Keyboard reference
• Mascot

Features at a glance

• Two panels, 0–3 columns per panel, adjustable split, one panel can be hidden.
• Colors by type: directories, executables, symlinks, broken links; files and directories with uncommitted git changes are orange.
• Preview in the second panel that follows the cursor: syntax highlighting for 30+ formats, logs, directory info, hex dump for binaries, archive listing.
• Built-in editor with smart indentation (.editorconfig, auto-detection, language defaults).
• Background search by content and by name over the whole subtree, results shown live in the preview.
• Copy / move with progress and a conflict dialog; delete to trash or permanently; rename in place.
• Archives open like directories (zip, tar, gz, tar.gz, tar.zst; rar/7z through external tools) and can be created from marked files.
• "Largest objects" mode: recursive sizes, share bars and a heat-map gradient.
• Drive picker: drive letters on Windows, mount points on macOS and Linux.
• Context-aware hint line, full help window, settings window.
• English and Russian interface, five color themes.
• When you quit, the shell changes into the directory of the active panel.

Installation

You need a Rust toolchain (edition 2024, Rust 1.88+).

macOS / Linux

git clone https://github.com/Pastor/janus.git

cd janus && make install

make install builds the release binary into ~/.cargo/bin/janus and adds the f shell function to ~/.zshrc, ~/.bashrc or fish's conf.d. Open a new terminal and run f: after you quit, the shell is left in the directory of the active panel (for an open archive — in the directory containing it). make uninstall removes both.

If you used it under its former name fmgr, make install removes the old binary and shell hook, and your settings are copied from ~/.config/fmgr on the first start.

Windows

cargo install --path . --locked

Then run janus in Windows Terminal or any terminal with VT support. Use g to switch between drives. The f shell function is not available for PowerShell or cmd yet.

Panels and navigation

There are always two panels and exactly one of them is active (highlighted border). The path is shown in the top border, the position counter and the number/size of marked files — in the bottom one.

• ↑ ↓ PgUp PgDn Home End move the cursor.
• → / Enter enter a directory or an archive, ← goes up and puts the cursor on the directory you came from. ← at the root opens the drive picker.
• Tab switches panels, < / > change the split, P hides or shows the second panel.
• 1 2 3 — number of columns. In multi-column mode files flow down the columns like ls; Shift+← / Shift+→ jump to the neighbouring column. Size and date are shown only with one column; 0 gives one column with names only.
• . toggles hidden files (the default is set in the settings).

Directories come first, in bold, with a trailing /. Executables are green, symbolic links blue, broken links red and struck through. With git installed, files and subdirectories with uncommitted changes (modified, staged, deleted, untracked) are orange; outside a working tree, repositories that contain such changes are highlighted instead. The status is computed in the background on every reread.

If a command key is pressed in a non-Latin keyboard layout, Janus does not silently ignore it — the status line says that the layout is wrong.

Preview

p opens a preview in the second panel. It follows the cursor of the file panel; Enter on a file opens the preview and moves focus into it.

What is under the cursor	What the preview shows
Text file	Syntax highlighting, line numbers for source code
Directory	Path, number of files and subdirectories, total size (counted in the background), permissions, owner, dates, the largest entries
Binary file	Type, size, permissions, dates, hex dump of the beginning
Archive	List of entries

In the preview: Tab moves focus between the panels, ↑↓ PgUp PgDn Home End scroll, w toggles soft wrap (← → shift the text when wrap is off), / searches the text as you type (the match is centered, ← → go to the previous / next one with a 3/17 counter), e opens the editor, p / Esc close.

Highlighting is done by an own line-based lexer:

Category	Formats
Languages	Rust, C/C++, Go, Java, Kotlin, Python, JS/TS, Lua, Ruby, Shell, Swift, C#, PHP
Markup	Markdown, HTML, XML, CSS
Data and config	JSON, YAML, TOML, INI, .properties, .env, .editorconfig
Other	SQL, Dockerfile, Makefile, .gitignore / .dockerignore / *ignore, diff/patch
Logs	*.log and files that look like a log

The format is detected by name and extension, or by the shebang and first lines. In logs, ERROR/FATAL are red, WARN yellow, DEBUG/TRACE dimmed; timestamps, IP addresses, URLs, numbers, quoted strings and stack traces are highlighted too.

Editor

e in the preview turns it into an editor.

• Arrows, Home End PgUp PgDn, Ctrl+Home / Ctrl+End; Home goes to the first non-blank character, pressed again — to the line start.
• Tab / Shift+Tab indent and dedent, Enter keeps the indentation and increases it after {, (, [ and : in Python.
• The indent size comes from .editorconfig, otherwise it is detected from the file, otherwise the language default is used (4 spaces for Rust, Python, C…; 2 for JS/TS, JSON, YAML…; tabs for Go and Makefile).
• Ctrl+S saves (with confirmation), Esc asks to save / discard / keep editing when there are changes.

Search

• / — search by content across the whole subtree of the current directory.
• f — search by name (substring).

Search runs in the background as you type. Binary files are skipped, hidden files follow the panel setting. Case is respected only if the query contains uppercase letters (the same rule applies to all searches). The second panel shows the found file with the match highlighted and centered; ↑ ↓ go through the matches (across files), Enter jumps to the file in the panel, Esc leaves the search.

Copy, move, delete

• Space marks a file and moves the cursor down; the bottom border shows the number and total size of the marked files.
• c copies and m moves the marked files (or the one under the cursor) into the directory of the other panel. A progress dialog is shown; Esc cancels.
• On a name conflict you choose: r replace, s skip, R replace all, S skip all, Esc cancel.
• d deletes to trash, D deletes permanently. Both ask for confirmation — press the same key again. In the settings you can make d delete permanently too.

Conflict	Permanent delete

Rename

r (or F2) renames the file or directory under the cursor right in the panel.

• The cursor starts before the extension: report|.pdf — usually you change the name, not the type. For directories and names like .gitignore it starts at the end.
• ← → Home End move inside the name, Backspace / Delete erase, any letters (Cyrillic included) are typed as text. Enter renames, Esc cancels.
• After renaming, the cursor stays on the item under its new name, and the other panel is refreshed if it shows the same directory.
• An existing name is never overwritten: the status line says "already exists". Changing only the case (readme.md → README.md) works on case-insensitive file systems too. Names with / (and \ : * ? " < > | on Windows) are rejected.
• Archives are read-only, so renaming inside an open archive is not allowed.

Archives

• Enter on an archive extracts it into a temporary directory in the background and the panel works inside it like in a normal folder. The title shows archive.zip/…. The temporary directory is removed when you leave the archive and on exit.
• Formats: zip, tar, gz, tar.gz/tgz, tar.zst. RAR and 7z are opened through unrar, 7z/7zz or bsdtar if one of them is installed.
• Archives are read-only: copying into them and editing their files is blocked, copying out of them works.
• a creates an archive from the marked files (or the item under the cursor) in the current directory: ← → choose the format (zip, tar, tar.gz, tar.zst), type the name, Enter creates.

Largest objects

l opens a full-screen view of the current directory: sizes are counted recursively in the background, entries are sorted by size with a share bar, a percentage and a color gradient. → / Enter go into a directory, ← goes up, d / D delete the object under the cursor (sizes of the parents are recalculated without a rescan). Esc returns to the panels and opens the current directory in the active one.

Drives and volumes

g (or ← at the root of a drive) opens the drive picker for the active panel.

• Windows: all drive letters with type (disk, removable, network, CD/DVD), volume label, a fill bar and free space. Press the drive letter to jump to it right away. No "insert a disk" system popups for empty card readers; network drives are not queried for free space so a disconnected share can't freeze the window.
• macOS: /, home directory and everything mounted in /Volumes.
• Linux: /, home directory and mounted block devices (USB sticks in /media, /run/media, /mnt, extra partitions), without /boot and snaps.

The cursor starts on the drive that contains the current directory. ↑ ↓ choose, Enter / → go, Esc closes.

Help, hints and settings

The bottom line shows only keys that will do something right now (for example, c / m appear only when there is somewhere to copy). If they don't fit, hints take two lines; whatever still doesn't fit becomes ….

? opens the full help with all keys grouped by mode, o opens the settings.

Help	Settings

Settings are applied immediately; Enter saves, Esc reverts:

• language: English / Русский;
• theme: Dark, Light, Gruvbox, Solarized, Nord;
• soft wrap in the preview;
• hidden files;
• default indent size;
• whether d moves to trash or deletes permanently.

-t and -l on the command line change the theme and language only for the current run; they are not written to the config.

Settings live in ~/.config/janus/config.toml (on all platforms). The session is saved there too: panel split, columns, hidden panel and the last directory of the right panel.

Themes

Dark is the default. The theme can be changed in the settings or with -t.

Light	Gruvbox
Solarized	Nord

Colors adapt to the terminal: truecolor, 256 colors or 16 colors.

Command line

janus [OPTIONS] [LEFT] [RIGHT]

Option	Meaning
LEFT, RIGHT	Directories for the panels. Without them the left panel opens in the current directory and the right one where it was last time
-t, --theme	dark, light, gruvbox, solarized, nord — for this run only
-l, --lang	en, ru — for this run only
--cwd-file FILE	On exit, write the directory of the active panel into FILE
--shell-init SHELL	Print the f function for zsh, bash or fish

Manual shell integration (what make install does):

eval "$(janus --shell-init zsh)"

Keyboard reference

Ctrl+C always quits. q quits from the file list, cancels a running operation, and acts as Esc in dialogs, help, settings, the preview and modes; in text input it is just a letter.

Panels

Key	Action
↑↓ PgUp PgDn Home End	Move the cursor
→ Enter	Enter a directory or an archive; open a file in the preview
←	Go up; from an archive root — back to the archive; at the root — drives
Tab	Switch panel
< >	Narrow / widen the active panel
P	Hide / show the second panel
0 1 2 3	Columns (0 — names only)
Shift+←→	Neighbouring column
.	Hidden files
g	Drive picker

Files

Key	Action
Space	Mark
c / m	Copy / move to the other panel
r F2	Rename
d / D	Delete to trash / permanently
a	Create an archive
p	Preview
/ / f	Search by content / by name
l	Largest objects
o / ?	Settings / help

Preview: Tab focus, ↑↓ PgUp PgDn scroll, ←→ shift, w wrap, / search, e edit, Esc close. Editor: Ctrl+S save, Esc close, Tab / Shift+Tab indent, Home, Ctrl+Home / Ctrl+End.

Mascot

Janus's mascot is a little owl whose facial disc is made of two "panels": the right eye is open — that's the active panel; the left eye is asleep while copying, search or size counting runs in the background. It sees everything, even when half of it is asleep.

SVG and PNG versions (including favicon sizes) and the usage guide live in docs/mascot. Distributed under the project's MIT license.

License

MIT