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Gforth is a fast and portable implementation of the ANS Forth language. It works nicely with the Emacs editor, offers some nice features such as input completion and history, backtraces, a decompiler and a powerful locals facility, and it has a comprehensive manual. Gforth combines traditional implementation techniques with newer techniques for portability and performance: its inner interpreter is direct threaded with several optimizations, but you can also use a traditional-style indirect threaded interpreter. Gforth is distributed under the GNU General Public license (see COPYING).

Supported Systems

Gforth runs under GNU, BSD, and similar systems, MS Windows and MacOS X and should not be hard to port to other systems supported by GCC. This version has been tested successfully on the following platforms:

  • GNU/Linux
    • amd64
    • arm64
    • armel
    • armhf
    • i386
    • mips
    • mipsel
    • powerpc
  • Android/Linux
    • amd64
    • arm64
    • arm
    • i386
    • mips
  • Gforth EC(embedded): r8c, 4stack, misc, 8086
  • Windows
    • amd64
    • i386
  • MacOS
    • amd64
    • i386


Read INSTALL for installation instructions from tarball,
or for from git,
or INSTALL.BINDIST if you have a binary package distributed as .tar.xz file.
If you received a self-installing executable, just run it and follow the instructions.

To start the system, just say gforth (after installing it).


You can find new versions of Gforth at
or at


On popular request, here are the meanings of unusual file extensions:

\*.fs Forth stream source file (include with "include _<file>_" from within gforth, or start with "gforth _<file1> <file2>_ ...")
\*.fi Forth image files (start with "gforth -i _<image file>_")
\*.fb Forth blocks file (load with "use _<block file>_ 1 load")
\*.i C include files
\* documenation source
\*TAGS etags files

A number of Forth source files are included in this package that are not necessary for building Gforth. Not all of them are mentioned in the rest of the documentation, so here's a short overview:


code.fs random.fs more.fs ansi.fs colorize.fs
oof.fs oofsampl.fs objects.fs blocked.fb tasker.fs


ans-report.fs etags.fs glosgen.fs filedump.fs


tt.fs sokoban.fs

Test programs (for testing Forth systems):



bubble.fs siev.fs matrix.fs fib.fs

ANS Forth implementations of Gforth extensions:





For discussions about Gforth, use the Usenet newsgroup comp.lang.forth. If you prefer not to post on Usenet, there is also a mailing list: You have to subsribe to post there. You can subscribe through The list is archived at

You can also report bugs through these channels, or you can report them through our bug database:

Authors: Bernd Paysan, Anton Ertl, Gerald Wodni Copyright (C) 1995,1996,1997,1998,2000,2003,2004,2006,2007,2008,2009,2016,2017,2018,2019,2020 Free Software Foundation, Inc.

This file is part of Gforth.

Gforth is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.#See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see

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