ESS - Emacs Speaks Statistics


1 General Information: README

This is the README file for the distribution of ESS version 13.09-2

ESS is a GNU Emacs and XEmacs mode for interactive statistical programming and data analysis. Languages supported: the S family (S, S-PLUS and R), SAS, BUGS/JAGS and Stata. ESS grew out of the desire for bug fixes and extensions to S-mode and SAS-mode as well as a consistent union of their features in one package.

Installation instructions are provided in sections for both Unix and Windows; see below.

The current development team is led by Martin Maechler since August 2004. Former project leader A.J. (Tony) Rossini ( did the initial port to XEmacs and has been the primary coder. Martin Maechler ( and Kurt Hornik ( have assisted with the S family and XLispStat. Stephen Eglen ( has worked mostly on R support. Richard M. Heiberger ( has assisted with S/S-PLUS development for Windows. Richard and Rodney A. Sparapani ( have done much of the work improving SAS batch and interactive support. Rodney has also extended ESS to support BUGS/JAGS and has an interest in improving Stata support.

We are grateful to the previous developers of S-mode (Doug Bates, Ed Kademan, Frank Ritter, David M. Smith), SAS-mode (Tom Cook) and Stata-mode (Thomas Lumley).

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1.1 License

The source and documentation of ESS 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 2, or (at your option) any later version.

ESS 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 in the file COPYING in the same directory as this file for more details.

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1.2 Stability

All recent released versions are meant to be release-quality versions. While some new features are being introduced, we are cleaning up and improving the interface. We know that there are many remaining opportunities for documentation improvements, but all contributors are volunteers and time is precious. Patches or suggested fixes with bug reports are much appreciated!

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1.3 Requirements

ESS is most likely to work with current/recent versions of the following statistical packages: R/S-PLUS, SAS, Stata, OpenBUGS and JAGS.

ESS supports current, and recent, stable versions of GNU Emacs (currently, specifically, the 23.x and 24.x series; alpha/beta/pre-release versions are NOT SUPPORTED). Non-Windows users beware: GNU Emacs 24.3 is preferable to 24.1 or 24.2: these broken builds suffer from bug 12463 which will cause emacs and ESS to get progressively slower over time.

Due to XEmacs lacking some features that ESS requires, ESS support of XEmacs ends with ESS 12.04-4. This decision will be re-visited in the future as XEmacs continues to sync with GNU Emacs.

To build the PDF documentation, you will need a version of TeX Live or texinfo that includes texi2dvi (BEWARE: recent TeX Live, and some texinfo RPMs, do NOT include texi2dvi).

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1.4 Getting the Latest Version

The latest released version of ESS is always available on the web at: ESS web page or StatLib

1.4.1 ESS subversion repository

The latest development version of ESS is available via, the ESS Subversion repository. If you have a Subversion client (see, you can download the sources using:

% svn checkout path

which will put the ESS files into directory path. Later, within that directory, ‘svn update’ will bring that directory up to date. Windows-based tools such as TortoiseSVN are also available for downloading the files. Alternatively, you can browse the sources with a web browser at: ESS SVN site. However, please use a subversion client instead to minimize the load when retrieving.

If you remove other versions of ESS from your emacs load-path, you can then use the development version by adding the following to .emacs:

(load "/path/to/ess-svn/lisp/ess-site.el") 

Note that https is required, and that the SSL certificate for the Subversion server of the R project is

Certificate information:
 - Hostname:
 - Valid: from Jul 16 08:10:01 2004 GMT until Jul 14 08:10:01 2014 GMT
 - Issuer: Department of Mathematics, ETH Zurich, Zurich, Switzerland, CH
 - Fingerprint: c9:5d:eb:f9:f2:56:d1:04:ba:44:61:f8:64:6b:d9:33:3f:93:6e:ad

(currently, there is no “trusted certificate”). You can accept this certificate permanently and will not be asked about it anymore.

1.4.2 Git for development

For development and experimentation on new features, there is now a GitHub branch for ESS, available at

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1.5 Installation

  1. Download the latest zip or tgz archive from ESS downloads area and unpack it into a directory where you would like ESS to reside. We will denote this directory as /path/to/ESS/ hereafter.

    Alternatively you can use svn or git to fetch the most recent development version to your local machine with:

    svn checkout /path/to/ESS


    git clone /path/to/ESS
  2. Optionally, compile elisp files and build the documentation with:
    cd /path/to/ESS/

    Without this step, info, pdf and html documentation and reference card will not be available.

  3. Optionally, install into your local machine with make install. You might need administrative privileges:
    make install

    The files are installed into /usr/share/emacs directory. For this step to run correctly on Mac OS X, you will need to adjust the PREFIX path in Makeconf. The necessary code and instructions are commented in that file.

  4. If you have performed the make install step from above, just add
    (require 'ess-site)

    to your ~/.emacs file. Otherwise, you should add /path/to/ESS/lisp/ to your emacs load path and then load ESS with the following lines in your ~/.emacs:

    (add-to-list 'load-path "/path/to/ESS/lisp/")
    (load "ess-site")
  5. Restart your Emacs and check that ESS was loaded from a correct location with M-x ess-version.

Note for Windows and Mac OS X users: The most straightforward way to install Emacs on your machine is by downloading all-in-one Emacs binary by Vincent Goulet.

Note for XEmacs users: Due to XEmacs lacking some features that ESS requires, ESS support of XEmacs ends with ESS 12.04-4. This decision will be re-visited in the future as XEmacs continues to sync with GNU Emacs.

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1.6 Starting an ESS process

To start an S session on Unix or on Windows when you use the Cygwin bash shell, simply type M-x S RET.

To start an S session on Windows when you use the MSDOS prompt shell, simply type M-x S+6-msdos RET.

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1.7 Current Features

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1.8 New Features

Changes / Selected Bug Fixes in 14.03:

Changes / Selected Bug Fixes in 13.09-1:

Changes/New Features in 13.09:

Changes/New Features in 13.05:

Changes/Bug Fixes in 12.09-2:

Changes/New Features in 12.09-1:

Bug Fixes in 12.09-1:

Changes/New Features in 12.09:

Changes/Bug Fixes in 12.04-3:

Changes/New Features in 12.04-1:

Bug Fixes in 12.04-1:

Changes/New Features in 12.04:

Changes/New Features in 12.03:

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1.9 Reporting Bugs

Please send bug reports, suggestions etc. to

The easiest way to do this is within Emacs by typing

M-x ess-submit-bug-report

This also gives the maintainers valuable information about your installation which may help us to identify or even fix the bug.

If Emacs reports an error, backtraces can help us debug the problem. Type "M-x set-variable RET debug-on-error RET t RET". Then run the command that causes the error and you should see a *Backtrace* buffer containing debug information; send us that buffer.

Note that comments, suggestions, words of praise and large cash donations are also more than welcome.

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1.10 Mailing Lists

There is a mailing list for discussions and announcements relating to ESS. Join the list by sending an e-mail with "subscribe ess-help" (or "help") in the body to; contributions to the list may be mailed to Rest assured, this is a fairly low-volume mailing list.

The purposes of the mailing list include

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1.11 Authors