ASAT — A Spreadsheet And Terminal

Terminal spreadsheet editor for Vim users. Modal editing (Normal/Insert/Visual/Command), 50+ live formulas, multi-sheet workbooks, CSV · XLSX · ODS support, full undo stack, system clipboard, named ranges, filter/freeze panes, cell notes, live conditional formatting, auto-fill series, macros, marks, . repeat, Python plugins, searchable help screen, and circular reference detection. Written in Rust with ratatui.

Website: https://okt4v.github.io/ASAT/

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Features

• Modal editing — Normal, Insert, Visual (char/line/block), Command, Search, and Macro Recording modes, exactly like Vim
• Live formula engine — 50+ built-in functions across math, text, logic, lookup, statistical, finance, and date. Includes volatile functions (NOW, TODAY, RAND, RANDBETWEEN) that recalculate every frame. =NOW() auto-displays as YYYY-MM-DD HH:MM; use :fmt datetime for other date-serial cells. Formulas re-evaluate after every edit (lazy dirty-cell tracking)
• Circular reference detection — cells that form dependency cycles display #CIRC! instead of crashing or hanging
• Named ranges — :name SALES A1:C10 defines a named range usable in formulas as =SUM(SALES)
• Multi-sheet workbooks — tab bar, :tabnew, :tabclose, gt / gT to switch sheets
• File format support — read and write CSV, TSV, XLSX, and ODS (OpenDocument Spreadsheet); native .asat format with bincode + zstd compression; ODS formula round-trip with cached computed values
• System clipboard — yank (yy, yc, visual y) copies values and styles as TSV; Ctrl+V in Insert mode pastes from system clipboard; delete (dd, x, visual d) also yanks to register + clipboard before clearing
• Formula-aware paste — pasting a formula adjusts relative cell references (A1 becomes B2 when pasted one row down and one column right); absolute references ($A$1) stay fixed; mixed references ($A1, A$1) lock only the $-prefixed axis
• Full undo stack — 1000-deep undo/redo covering cell edits, row/column operations, pastes, and style changes; undo/redo repositions the cursor to the affected cell
• Sort & find/replace — :sort [COL] [!] sorts rows by any column (e.g. :sort B! = column B descending); :s/pat/repl/g does regex find & replace across cells; both undoable
• Filter rows — :filter <col> <op> <val> hides non-matching rows (supports =, !=, >, <, >=, <=, ~); :filter off restores all rows
• Freeze panes — frozen rows and columns render as sticky headers with a visual separator; set via :freeze rows N / :freeze cols N
• Fill down / right — Ctrl+D / Ctrl+R in Visual mode copies anchor cell across selection; also :filldown / :fillright ex-commands
• Auto-fill series — Ctrl+F / Ctrl+E in Visual mode detects and extends arithmetic sequences, weekday names, and month names across the selection
• Live conditional formatting — :cf <range> <cond> <val> bg=#hex applies colour rules that re-evaluate every frame; supports >, <, >=, <=, =, !=, contains, blank, error; :cf clear removes all rules
• Formula color distinction — formula cells render in muted blue to distinguish them from literal data at a glance
• Live formula preview — while typing a formula, the current evaluated result appears in the formula bar as → value
• Cell reference highlighting — when the cursor rests on a formula cell, all referenced cells are highlighted in the grid
• Go-to definition — gd in Normal mode jumps to the first cell referenced in the current cell's formula
• Visual mode ex-commands — press : from Visual/V-Row/V-Col mode to enter a command that applies to the entire selection (e.g. :bold, :fg #ff0000, :sort)
• Repeat last change — . in Normal mode replays the last insert or delete operation (like Vim)
• Goto cell — g<letter> jumps to a column; :goto B15 jumps to any cell address
• Transpose — :transpose swaps rows and columns in the visual selection
• Remove duplicates — :dedup removes duplicate rows by the current cursor column
• Cell notes — :note <text> attaches a comment to the current cell; cells with notes show a ▸ corner marker; :note with no argument shows the current note; :note! clears it
• Thousands separator — :fmt thousands formats numbers with comma separators (#,##0); :fmt t2 adds two decimal places
• Formula tab-completion — press Tab while typing a formula (=SU…) to cycle through matching function names
• Time-based autosave — configurable autosave interval in seconds (edit autosave_interval in config.toml; 0 = disabled)
• Macros — record key sequences to named registers (qa … qz), replay with @a, chain with {N}@a
• Marks — set named positions (ma), jump back ('a), and swap with ''
• Cell merging — merge a visual selection into one spanning cell with M in Visual mode or :merge; unmerge with U or :unmerge; line wrap flows text into covered rows below the anchor
• Line wrap — toggle per-cell line wrap with gw (Normal mode) or :wrap; text reflows into merged rows below for vertical merges, and row height auto-expands for single cells
• Cell styling — bold, italic, underline (text-only by default; :underline full extends the underline across the full cell width), strikethrough, foreground/background colour, alignment, and number formats
• Themes — built-in theme picker (:theme) with multiple colour presets, saved to config
• Formula reference picker — press Ctrl+R inside a formula to navigate the grid and insert cell/range references interactively
• Searchable help screen — :help / :h opens a full-screen overlay with Keybindings and Formulas tabs; type to filter, Tab to switch tabs, j/k to scroll, q to close
• Plugin system — extend ASAT with Python via PyO3 (enabled by default); hook into cell changes, mode transitions, and file events; register custom formula functions from ~/.config/asat/init.py; manage plugins with :plugins

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Installation

Pre-built binaries (GitHub Releases)

Download a binary for your platform from the v0.1.28 release:

Platform	Link
Linux x86_64 (glibc)	asat-x86_64-unknown-linux-gnu.tar.gz
Linux x86_64 (musl)	asat-x86_64-unknown-linux-musl.tar.gz
Linux aarch64	asat-aarch64-unknown-linux-gnu.tar.gz
macOS arm64	asat-aarch64-apple-darwin.tar.gz
macOS x86_64	asat-x86_64-apple-darwin.tar.gz
Windows x86_64	asat-x86_64-pc-windows-msvc.zip

Extract the archive and place the asat binary somewhere on your $PATH (e.g. ~/.local/bin/).

Arch Linux (AUR)

yay -S asat-bin
# or
paru -S asat-bin

Homebrew (macOS / Linux)

brew tap okt4v/tap
brew install asat

Debian / Ubuntu (apt)

curl -LO https://github.com/okt4v/ASAT/releases/download/v0.1.28/asat_0.1.28-1_amd64.deb
sudo apt install ./asat_0.1.28-1_amd64.deb

apt install ./file.deb resolves dependencies automatically and registers the package so apt remove asat works as expected.

Build from source

git clone https://github.com/okt4v/ASAT.git
cd ASAT
bash install.sh

The install script builds in release mode and copies the binary to ~/.local/bin/asat. It will warn you if that directory is not on your $PATH.

To build manually instead:

cargo build --release
cp target/release/asat ~/.local/bin/

Note: The Python plugin engine is enabled by default. To build without it (smaller binary, no Python dependency): cargo build --release --no-default-features

Run

asat                   # open welcome screen
asat file.csv          # open a CSV file
asat budget.xlsx       # open an Excel workbook
asat report.ods        # open an ODS file
asat new_file.csv      # create a new file at this path

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Keybind Reference

Normal Mode — Navigation

Key	Action
h / ←	Move left
j / ↓	Move down
k / ↑	Move up
l / →	Move right
w / b	Jump to next / previous non-empty cell (horizontal)
W / B	Jump to next / previous non-empty cell (vertical)
} / {	Jump to next / previous paragraph boundary (empty row)
0 / Home	Jump to first column
$ / End	Jump to last column with data
gg	Jump to first row
G	Jump to last row with data
H / M / L	Jump to top / middle / bottom of visible area
f{A-Z}	Jump to column by letter (fC → column C)
Ctrl+d / Ctrl+f / PgDn	Page down
Ctrl+u / Ctrl+b / PgUp	Page up
zz / zt / zb	Scroll cursor to centre / top / bottom of screen
{N} + motion	Repeat motion N times (e.g. 5j moves down 5 rows)

Normal Mode — Editing

Key	Action
i / Enter / F2	Edit current cell
a	Edit current cell (append)
s / cc	Clear cell and enter insert mode
ci" / ci( / ci[ / ci{	Change inner text object — clear content inside delimiters and edit
.	Repeat last change (last insert, delete, or destructive key)
r	Enter replace mode
x / Del / D	Delete cell content (supports count, e.g. 3x)
~	Toggle case of text cell (supports count)
J	Join cell below into current cell (space-separated), clear below
gd	Jump to the first cell referenced in the current formula
Ctrl+a	Increment number / cycle date forward (day → month → weekday)
Ctrl+x	Decrement number / cycle date backward
gw	Toggle line wrap on current cell
U	Unmerge cell under cursor
o / O	Insert row below / above and enter insert mode
u	Undo
Ctrl+r	Redo

Normal Mode — Yank & Paste

Key	Action
yy / yr	Yank current row → register + system clipboard
yc	Yank current cell → register + system clipboard
yC	Yank entire column → register + system clipboard
yj / yk	Yank row below / above cursor
yS	Copy current cell's style to style clipboard
p / P	Paste after / before cursor (supports count)
pS	Paste style clipboard onto current cell

Normal Mode — Rows & Columns

Key	Action
dd	Delete current row
dc	Clear cell content (alias for x)
dC	Delete current column
dj / dk	Delete row below / above cursor
>> / <<	Increase / decrease current column width
=	Auto-fit current column to widest content
+ / -	Increase / decrease current row height
_	Reset row height to auto

Insert Mode (while editing a cell)

Key	Action
Esc	Confirm edit, return to Normal
Enter	Confirm edit, move down
Tab	Confirm edit, move right
Ctrl+a	Move edit cursor to start
Ctrl+e	Move edit cursor to end
Ctrl+w	Delete word backward
Ctrl+u	Delete to start of buffer
Ctrl+k	Delete to end of buffer
Ctrl+r	Enter F-REF mode to pick a cell/range reference (formulas only)
Ctrl+v	Paste from system clipboard into edit buffer
Tab / Shift+Tab	Cycle through formula function name completions (when buffer starts with =)

Visual Mode

Key	Action
v	Character/cell visual mode
V	Line (full-row) visual mode
Ctrl+v	Column block visual mode
M	Merge selection into one spanning cell
d / x / Del	Delete selection
c / s	Clear selection and enter insert mode
y	Yank selection → register + system clipboard (TSV)
S	Insert =SUM(range) below the selection
> / <	Widen / narrow all columns in selection
Ctrl+d	Fill down — copy anchor row to all selected rows
Ctrl+r	Fill right — copy anchor column to all selected columns
Ctrl+f	Auto-fill series down — extends arithmetic, weekday, or month patterns
Ctrl+e	Auto-fill series right
:	Enter Command mode with the selection range pre-loaded (e.g. :bold, :fg #hex)

Marks & Macros

Key	Action
m{a-z}	Set named mark
'{a-z}	Jump to named mark
''	Jump back to position before last jump
q{a-z}	Start recording macro to register
q	Stop recording
@{a-z}	Play macro from register
@@	Replay last macro
{N}@{reg}	Play macro N times

Search

Key	Action
/	Forward search (regex supported)
?	Backward search
n / N	Next / previous match
*	Search for content of current cell

Sheets

Key	Action
Tab / gt / Ctrl+t	Next sheet
Shift+Tab / gT / Ctrl+T	Previous sheet

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Ex Commands

Enter command mode with :. From Visual mode, : pre-loads the current selection range so style and formatting commands apply to all selected cells.

Tab-completion works in command mode — press Tab to cycle through matching commands.

Command	Action
:w [file]	Save (optionally to a new path)
:q / :q!	Quit / force quit
:wq / :x	Save and quit
:e <file>	Open file
:tabnew [name]	New sheet
:tabclose	Close current sheet
:ic / :icr	Insert column left / right
:dc	Delete current column
:ir [N]	Insert row at cursor or line N
:dr [N]	Delete row at cursor or line N
:cw <N>	Set column width to N characters
:rh <N>	Set row height to N lines
:bold / :italic / :underline / :underline full / :strike	Toggle text style; :underline underlines text characters only; :underline full extends the underline across the full cell width
:fg <color> / :bg <color>	Set foreground / background colour (hex or named)
:hl <color> / :hl	Highlight cell / clear highlight
:align <l/c/r>	Set alignment: left, center, or right
:fmt <spec>	Number format: %, $, 0.00, int, date, none
:cs	Clear all styles
:theme [name]	Open theme picker or apply a theme by name
:sort [COL] [!]	Sort by column letter (e.g. :sort A, :sort B! = descending); defaults to cursor column (undoable)
:s/pat/repl/[g][i]	Find & replace in text cells — g = all occurrences, i = case-insensitive (undoable)
:goto <addr> / :go <addr>	Jump to cell address (e.g. :goto B15)
:name <NAME> <range>	Define a named range (e.g. :name SALES A1:C10)
:filter <col> <op> <val>	Hide rows where column does not match (ops: = != > < >= <= ~)
:filter off	Unhide all filtered rows
:transpose / :tp	Transpose the visual selection (swap rows and columns)
:dedup	Remove duplicate rows by the current cursor column
:note [text]	Set a note on current cell; :note shows it; :note! clears it
:cf <range> <cond> <val> bg=#hex [fg=#hex]	Add live conditional format rule (e.g. :cf A1:C10 > 100 bg=#ff0000); conditions: > < >= <= = != contains blank error
:cf clear	Remove all conditional format rules from the active sheet
:cf list	Show number of active conditional format rules
:filldown / :fd	Fill the cursor cell value down to the selection end
:fillright / :fr	Fill the cursor cell value right to the selection end
:fmt thousands / :fmt t2	Thousands-separator number format (#,##0 or #,##0.00)
:freeze rows <N>	Freeze top N rows as sticky header
:freeze cols <N>	Freeze left N columns as sticky header
:freeze off	Clear all frozen panes
:merge	Merge visual selection (or current cell) into one spanning cell
:unmerge	Unmerge the merged region under the cursor
:wrap / :ww	Toggle line wrap on current cell or selection
:help / :h	Open full-screen searchable help (Keybindings + Formulas tabs)
:home	Return to the welcome / home screen
:plugins	Open plugin manager TUI

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Formula Engine

Start any cell with = to write a formula. Formulas re-evaluate automatically after every edit.

=SUM(A1:A10)
=IF(B2>100, "Over budget", "OK")
=AVERAGE(C1:C20) * 1.1
=CONCATENATE(A1, " ", B1)
=NOW()              → current date and time (recalculates every frame)
=RAND()             → random float between 0 and 1

Supported functions:

Category	Functions
Math	SUM, AVERAGE, MIN, MAX, ABS, ROUND, ROUNDUP, ROUNDDOWN, FLOOR, CEILING, MOD, POWER, SQRT, LN, LOG, LOG10, EXP, INT, TRUNC, SIGN
Text	LEN, LEFT, RIGHT, MID, TRIM, UPPER, LOWER, PROPER, CONCATENATE, TEXT, VALUE, FIND, SEARCH, SUBSTITUTE, REPLACE, REPT
Logic	IF, AND, OR, NOT, ISNUMBER, ISTEXT, ISBLANK, ISERROR, IFERROR, ISLOGICAL
Lookup	VLOOKUP, HLOOKUP, XLOOKUP, INDEX, MATCH, OFFSET, CHOOSE
Date	NOW, TODAY, DATE, YEAR, MONTH, DAY
Random	RAND, RANDBETWEEN
Statistical	COUNT, COUNTA, SUMIF, COUNTIF, AVERAGEIF, MAXIFS, MINIFS, SUMPRODUCT, MEDIAN, STDEV, VAR, LARGE, SMALL, RANK, PERCENTILE, QUARTILE
Finance	PV, FV, PMT, NPER, RATE, NPV, IRR, MIRR, IPMT, PPMT, SLN, DDB, EFFECT, NOMINAL, CUMIPMT, CUMPRINC
Constants	TRUE, FALSE, PI()

Volatile functions (NOW, TODAY, RAND, RANDBETWEEN) recalculate on every frame, not just on cell edits.

Circular references: If a formula creates a dependency cycle (e.g. A1=B1+1 and B1=A1+1), all cells in the cycle display #CIRC!. Break the cycle by editing one of the cells.

Reference syntax:

Syntax	Meaning
A1	Relative cell reference (adjusts on paste)
$A$1	Absolute cell reference (fixed on paste)
$A1 / A$1	Mixed reference (lock column or row only)
A1:B10	Range
Sheet2!C4	Cross-sheet reference

Interactive reference picking: While editing a formula, press Ctrl+R to enter F-REF mode. Navigate with hjkl/arrows. Press v (or :) to anchor a range start, then move to the end cell and press Enter to insert the range reference (e.g. A1:C5). Press Enter without anchoring to insert a single cell reference. Press Esc to cancel. The formula bar continues to show your in-progress formula throughout.

Financial Functions

Function	Signature	Description
PV	PV(rate, nper, pmt, [fv], [type])	Present value of an investment or annuity
FV	FV(rate, nper, pmt, [pv], [type])	Future value of an investment or annuity
PMT	PMT(rate, nper, pv, [fv], [type])	Periodic payment for a loan or annuity
NPER	NPER(rate, pmt, pv, [fv], [type])	Number of periods to pay off a loan
RATE	RATE(nper, pmt, pv, [fv], [type], [guess])	Interest rate per period (iterative)
NPV	NPV(rate, cf1, cf2, …)	Net present value of a series of cashflows
IRR	IRR(values, [guess])	Internal rate of return (iterative)
MIRR	MIRR(values, finance_rate, reinvest_rate)	Modified internal rate of return
IPMT	IPMT(rate, per, nper, pv, [fv], [type])	Interest portion of a payment
PPMT	PPMT(rate, per, nper, pv, [fv], [type])	Principal portion of a payment
CUMIPMT	CUMIPMT(rate, nper, pv, start, end, type)	Cumulative interest paid over a range of periods
CUMPRINC	CUMPRINC(rate, nper, pv, start, end, type)	Cumulative principal paid over a range of periods
SLN	SLN(cost, salvage, life)	Straight-line depreciation per period
DDB	DDB(cost, salvage, life, period, [factor])	Double-declining balance depreciation
EFFECT	EFFECT(nominal_rate, npery)	Effective annual interest rate
NOMINAL	NOMINAL(effect_rate, npery)	Nominal annual interest rate

Convention: pv/pmt follow the Excel cash-flow sign convention (money paid out is negative). type = 0 means end-of-period payments (default), 1 means beginning-of-period.

Examples:

=PMT(5%/12, 360, 200000)         → monthly payment on a 30yr £200k mortgage at 5%
=PV(8%/12, 60, -500)             → present value of 60 monthly payments of £500
=FV(6%/12, 120, -200, -5000)     → future value after 10yrs of £200/mo + £5k lump sum
=NPV(10%, -10000, 3000, 4000, 5000, 6000)  → NPV of a project at 10% discount rate
=IRR({-10000, 3000, 4000, 5000}) → IRR of a cashflow series
=IPMT(5%/12, 1, 360, 200000)     → interest paid in month 1 of the mortgage above
=SLN(50000, 5000, 5)             → £9000/yr straight-line depreciation
=EFFECT(5%, 12)                  → effective annual rate for 5% nominal compounded monthly

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Help Screen

Press :help (or :h) to open a full-screen searchable help overlay.

• Keybindings tab — all Normal, Insert, and Visual mode keybinds organized by category
• Formulas tab — all 50+ built-in functions with one-line descriptions
• Search — type any text to filter entries across both tabs instantly
• Navigation — j/k to scroll, Tab to switch tabs, q or Esc to close

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Configuration

ASAT reads a config file on startup at ~/.config/asat/config.toml (respects $XDG_CONFIG_HOME).

Press c on the welcome screen to open it in your $EDITOR. The file is created automatically with all options commented on first open.

# Select a built-in theme by name — no hex values needed
theme_name = "nord"

# Display
default_col_width    = 10
min_col_width        = 3
max_col_width        = 60
scroll_padding       = 3
show_line_numbers    = false
relative_line_numbers = false
highlight_cursor_row = false
highlight_cursor_col = false
show_formula_bar     = true
show_tab_bar         = true
show_status_bar      = true
status_timeout       = 3      # seconds before status message fades (0 = never)

# Editing
undo_limit           = 1000
autosave_interval    = 0      # seconds between auto-saves (0 = disabled)
backup_on_save       = false  # write a .bak before overwriting
confirm_delete       = false  # ask before dd / :dr / :dc
wrap_navigation      = false  # wrap cursor at sheet edges

# Number formatting
number_precision     = 6      # max decimal places for unformatted numbers
date_format          = "YYYY-MM-DD"

# Files
default_format       = "csv"  # fallback format when saving without extension
csv_delimiter        = ","
remember_recent      = 20     # files shown on welcome screen

# Custom colors — only used when theme_name = "custom" or ""
# [theme]
# cursor_bg = "#268BD2"
# cell_bg   = "#002B36"
# ...

Built-in themes: solarized-dark, solarized-light, nord, dracula, gruvbox-dark, gruvbox-light, tokyo-night, catppuccin-mocha, catppuccin-latte, one-dark, monokai, rose-pine, everforest-dark, kanagawa, cyberpunk, amber-terminal, ice, github-dark

Browse and apply themes interactively with :theme.

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Plugin System

ASAT includes a Python plugin engine via PyO3, enabled by default. Place your script at ~/.config/asat/init.py — it is loaded on startup and can be hot-reloaded with :plugin reload.

import asat

# React to events
@asat.on("cell_change")
def on_change(sheet, row, col, old, new):
    if isinstance(new, (int, float)) and new > 1_000_000:
        asat.notify("Very large value!")

@asat.on("mode_change")
def on_mode(mode):
    if mode == "INSERT":
        asat.notify("Editing...")

# Register custom formula functions (callable as =DOUBLE(A1))
@asat.function("DOUBLE")
def double(x):
    return x * 2

# Read/write cells by address
@asat.on("open")
def on_open(path):
    asat.write("A1", "Loaded: " + str(path))
    val = asat.read("B2")

Available events: open, pre_save, post_save, cell_change, mode_change, sheet_change

Plugin API: asat.notify(msg), asat.command(cmd), asat.read("A1"), asat.write("A1", val), asat.get_cell(row, col), asat.set_cell(row, col, val)

Commands: :plugins — open the plugin manager TUI (shows engine status and registered custom functions); :plugin reload — hot-reload init.py; :plugin list — list loaded handlers

To build without Python (smaller binary, no Python dependency):

cargo build --release --no-default-features

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File Formats

Format	Read	Write	Notes
.csv / .tsv	✅	✅	Active sheet only
.xlsx	✅	✅	Multi-sheet, via calamine + rust_xlsxwriter
.xls / .xlsm	✅	—	Read via calamine
.ods	✅	✅	Multi-sheet OpenDocument Spreadsheet
.asat	✅	✅	Native format — bincode + zstd, multi-sheet

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Crate Architecture

ASAT is structured as a Cargo workspace with focused, single-responsibility crates:

crates/
  asat-core/      — Workbook, Sheet, Cell, CellValue, CellStyle (no internal deps)
  asat-formula/   — Lexer, parser (AST), evaluator, 50+ built-in functions
  asat-io/        — CSV, XLSX, ODS, .asat drivers (calamine read / rust_xlsxwriter write)
  asat-tui/       — ratatui widgets: grid, formula bar, status bar, tab bar, command line
  asat-input/     — Modal state machine, InputState, AppAction enum
  asat-commands/  — Command trait, UndoStack, SetCell, InsertRow/Col, DeleteRow/Col
  asat-plugins/   — Plugin manager: PyO3 Python backend (enabled by default)
  asat-config/    — Config struct, config.toml parsing, ThemeConfig
  asat/           — Binary: main loop, AppAction dispatch, ex-command handler

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License

GNU General Public License v3.0 — see LICENSE for details.

Any fork or modified version distributed publicly must remain open source, credit the original authors, and use the same license.