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This manual is for emacs-wiki version 2.72.

For a list of the copyright holders, Contributors

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU General Public License.

--- The Detailed Node Listing ---


Markup Rules


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1 Preface

This document describes emacs-wiki, which was written by John Wiegley and is now maintained by Michael Olson.

This document is a work in progress, and your contribution will be greatly appreciated. Please email comments and suggestions to the maintainer, Michael Olson [email protected] .

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2 Introduction

emacs-wiki enables you to create and use hyperlinks and simple formatting in plain text files, and to optionally publish your pages as HTML.

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3 Installation

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3.1 Installing a release

Choose to install a release if you want to minimize risk.

Errors are corrected in development first. Once fixes are confirmed, a new release will be made. User-visible changes will be announced on the [email protected] mailing list. see Getting Help and Reporting Bugs.

Debian users can get emacs-wiki via apt-get. The version of emacs-wiki in the Debian stable archive is not recommended, since it is so old. emacs-wiki is available in the Sarge and Sid distributions: apt-get install emacs-wiki .

You can also install the source distribution.

  1. Download and unpack the latest version from http://www.mwolson.org/static/dist/emacs-wiki/ .
  2. Edit your ~/.emacs.
              ;; Add the directories to your load path
              (add-to-list 'load-path "/path/to/emacs-wiki")
              ;; Load emacs-wiki
              (require 'emacs-wiki)

You can download the archive at the following locations:

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3.2 Installing the development version

Choose the development version if you want to live on the bleeding edge of emacs-wiki development or try out new features before release.

The Arch revision control system allows you to retrieve previous versions and select specific features and bug fixes.

Downloading the modules for the first time:

  1. Install arch. Debian: apt-get install tla . Other distros: see http://regexps.srparish.net/www/ .
  2. Register the archive and download the modules.
              # Register the archive
              tla register-archive http://www.mwolson.org/archives/2005
              # Download emacs-wiki module into the emacs-wiki/ subdirectory
              tla get [email protected]/emacs-wiki--main--1.0 emacs-wiki
  3. Open your ~/.emacs and add the emacs-wiki/ directory to your load path.
              (add-to-list 'load-path "/path/to/emacs-wiki")

To list upstream changes not in local copy:

     # Change to the source directory you are interested in. Example:
     cd emacs-wiki/
     # Display the summary of changes
     tla missing --summary

To update to the latest version:

     cd emacs-wiki
     tla replay

You can also obtain the archive at the following locations on the web:

The latest development snapshot will be kept up to date since it is updated at the same time as the Arch repository.

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4 Wiki Concepts

Wiki is a concept, more than a thing. It is a way of creating document pages using plain text markup and simplified hyperlinking.

By typing a name in MixedCase (also known as CamelCase), a hyperlink is automatically created to the document MixedCase. Pressing return on that name will create the file if it doesn't exist, or visit it if it does.

The markup used by Emacs-Wiki is intended to be very friendly to people familiar with Emacs. Type C-h v emacs-wiki-publishing-markup after this mode is loaded for more information on how to get started.

Wiki's are often associated with sites that allow collaborative editing of a website. emacs-wiki is not meant to produce this sort of site, although you can use Emacs to serve web pages. See emacs-wiki-httpd.el for more information. Note that this feature is not well-tested.

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5 Getting Started

To begin using Emacs-Wiki, put this in your .emacs file:

     (load ``emacs-wiki'')

Now you can type M-x emacs-wiki-find-file, give it a WikiName (or just hit return) and start typing!

You should also type M-x customize-group, and give the name ‘emacs-wiki’. Change it to suit your preferences. Each of the options has its own documentation.

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6 Keystroke Summary

Here is a summary of keystrokes available in every Wiki buffer:

C-c C-a
Jump to an index of all the Wiki pages.
C-c C-b
Show all pages that reference this page.
C-c C-s
Search for a word in your Wiki pages.
C-c C-f
Jump to another Wiki page. Prompt for the name.
C-c C-l
Highlight/refresh the current buffer.
C-c C-p
Publish any Wiki pages that have changed as HTML.
C-c C-r
Rename Wiki link at point.
C-c C-t
Publish the current Wiki page.
C-c C-e
Edit link at point.
C-c C-v
Change Wiki project.
C-c C-D
Delete Wiki link at point. This binding will only work on X.
C-c =
Diff this page against the last backup version.
Insert a tag interactively.
Move to the next Wiki reference.
Move to the previous Wiki reference.

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7 Markup Rules

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7.1 Basic WikiMarkups

Here is a description of the default markup rules:


      * First level
      ** Second level
      *** Third level

Note that the first level is actually indicated using H2, so that it doesn't appear at the same level as the page heading (which conceptually titles the section of that Wiki page).

Horizontal rules



      **strong emphasis**
      ***very strong emphasis***
      _underlined text_
      <verbatim>This tag should be used for larger blocks of text</verbatim>.


A reference[1], which is just a number in square brackets, constitutes a footnote reference.


      [1]  Footnotes are defined by the same number in brackets
           occurring at the beginning of a line.  Use footnote-mode's C-c
           ! a command, to very easily insert footnotes while typing.  Use
           C-x C-x to return to the point of insertion.


One or more blank lines separates paragraphs.

Centered paragraphs and quotations

A line that begins with six or more columns of whitespace (made up of tabs or spaces) indicates a centered paragraph. I assume this because it's expected you will use M-s to center the line, which usually adds a lot of whitespace before it.

If a line begins with some whitespace, but less than six columns, it indicates a quoted paragraph.

Poetic verse

Poetry requires that whitespace be preserved, without resorting to the monospace typical of <pre>. For this, the following special markup exists, which is reminiscent of e-mail quotations:

       > A line of Emacs verse;
       > forgive its being so terse.

You can also use the <verse> tag, if you prefer:

       A line of Emacs verse;
       forgive its being so terse.

Literal paragraphs

Use the HTML tags <pre></pre> to insert a paragraph and preserve whitespace. If you're inserting a block of code, you will almost always want to use <verbatim></verbatim> *within* the <pre> tags. The shorcut for doing this is to use the <example> tag:

       Some literal text or code here.


There are two forms of table markup supported. If Takaaki Ota's table.el package is available, then simply create your tables using his package, and they will be rendered into the appropriate HTML. You need to (require 'emacs-wiki-table) for this functionality.

If table.el is not available, then only very simple table markup is supported. The attributes of the table are kept in `emacs-wiki-table-attributes'. The syntax is:

       Double bars || Separate header fields
       Single bars | Separate body fields
       Here are more | body fields
       Triple bars ||| Separate footer fields

Other paragraph markup applies to both styles, meaning that if six or more columns of whitespace precedes the first line of the table, it will be centered, and if any whitespace at all precedes first line, it will occur in a blockquote.

Anchors and tagged links

#example If you begin a line with "#anchor" – where anchor can be any word that doesn't contain whitespace – it defines an anchor at that point into the document. This anchor text is not displayed.

You can reference an anchored point in another page (or even in the current page) using WikiName#anchor. The #anchor will never be displayed in HTML, whether at the point of definition or reference, but it will cause browsers to jump to that point in the document.

Redirecting to another page or URL

Sometimes you may wish to redirect someone to another page. To do this, put:

       <redirect url=\"http://somewhereelse.com\"/>

at the top of the page. If the <redirect> tag specifies content, this will be used as the redirection message, rather than the default.

The numbers of seconds to delay is defined by `emacs-wiki-redirect-delay', which defaults to 2 seconds. The page shown will also contain a link to click on, for browsing which do not support automatic refreshing.


A regular URL is given as a link. If it's an image URL, it will be inlined using an IMG tag.

Special handling of WikiNames

If you need to add a plural at the end of a WikiName, separate it with four single quotes (WikiName””s) or make it an explicit link ([[WikiName]]s).

To prevent a link name (of any type) from being treated as such, surround it with =equals= (to display it in monotype), or prefix it with the tag <nop> to escape it from WikiName markup.

Special Wiki links

Besides the normal WikiName type links, emacs-wiki also supports extended links:

       [[link text][optional link description]]

An extended link is always a link, no matter how it looks. This means you can use any file in your `emacs-wiki-directories' as a Wiki file. If you provide an optional description, that's what will be shown instead of the link text. This is very useful for providing textual description of URLs.

See the documentation to emacs-wiki-image-regexp for how to inline files and images.

InterWiki names

There are times when you will want to constantly reference pages on another website. Rather than repeating the URL ad nauseum, you can define an InterWiki name. This is a set of WikiNames to URL correlations, that support textual substitution using #anchor names (which are appended to the URL). For example, MeatballWiki is defined in the variable `emacs-wiki-interwiki-names'. It means you can reference the page \"MeatBall\" on MeatballWiki using this syntax:


In the resulting HTML, the link is simply shown as


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7.2 Changing Title or Stylesheet

For convenience, if you want to change the visible title or the stylesheet used by a certain Wiki page during HTML publishing, just put:

     #title Hello there
     #style hello.css

at the top of the page.

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7.3 Lists

Whitespace is required after bullets and numbers thot are part of a list.

Here is an example:

     - This
     - Is
     - A
     - List
     1. This
     2. too
     But this is not,
     --even if it starts with dashes
     0.1] or numbers, as in the original test case.


There is no inherent support for sub-lists, since the author couldn't think of a simple way to do it. But if you really need them, here's a trick you can use:

      - Hello
        <li>My friend

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7.4 Images

You can include links of the form ‘[[some/link][some/image]]’. If you want to include alt text, use ‘[[some/link][some/image alt text]]’.

You may need to have auto-image-file-mode set to ‘t’ for this to work.

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7.5 Lisp Tricks

<lisp></lisp> tags can be used, not only to evaluate forms for insertion at that point, but to influence the publishing process in many ways. Here's another way to change a page's stylesheet:

       ;; use special.css for this Wiki page
       (set (make-variable-buffer-local 'emacs-wiki-style-sheet)
            "<link rel=\"stylesheet\" type=\"text/css\" href=\"special.css\" />"))

The ignore is needed so nothing is inserted where the <lisp> tag occurred. Also, there should be no blank lines before or after the tag (to avoid empty paragraphs from being created). The best place to put this would be at the very top or bottom of the page.

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7.6 Non-existent Links

By default, non-existent links are converted into mailto: links in published HTML. This allows website visitors to e-mail emacs-wiki-maintainer for missing information. If you want non-existent links to be rendered as plain text, set emacs-wiki-markup-nonexistent-link to nil.

In HTML served directly from Emacs using httpd and emacs-wiki-httpd.el, non-existent links are always editable links.

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7.7 Special Markups

For specially marking up Wiki text, XML-style tags are the best way to add custom markup to Emacs Wiki, which expects a closing tag and/or an optional set of attributes. This is easily accomplished by customizing this list of markup tags defined in emacs-wiki-markup-tags.

Here is a summary of the default tags. This also includes the dangerous tags listed in emacs-wiki-dangerous-tags, which may not be used by outsiders.

Please refer to document of emacs-wiki-markup-tags and emacs-wiki-dangerous-tags for detail infomation and customization instructions.


Protects against highlighting and wiki interpretation, and escapes any characters which have special meaning to the publishing format. For HTML, this means characters like '<' are escaped as HTML entities.


Like verbatim, but typesets in HTML using the <pre> tag, with class=example, so whitespace formatting is preserved.


Inhibits wiki markup, but does not do any escaping to the underlying publishing medium. Useful for embedding HTML, PHP, etc.


Typesets like a normal paragraph, but without word-wrapping. That is, whitespace is preserved.


Using the "url" attribute, you can specify that a page should redirect to another page. The remaining contents of the page will not be published. The optional "delay" attribute specifies how long to wait before redirecting.


When placed before a WikiLink, it will prevent that WikiLink from being treated as such. Good for names like DocBook.


Produces a compact table of contents for any section heading at the same level or lower than the next section header encountered. Optional "depth" attribute specifies how deep the table of contents should go.


Evaluate the region as a Lisp form, and displays the result. When highlighting, the `display' text property is used, preserving the underlying text. Turn off font-lock mode if you wish to edit it.


Pass the region to a command interpretor and insert the result, guarding it from any further expansion. Optional "file" attribute specifies the shell or interpretor to use. If none is given, and emacs-wiki-command-tag-file has not been configured, Eshell is used.

python, perl

Pass the region to the Python or Perl language interpretor, and insert the result.


Markup the region as C or C++ source code, using the c2html program, if available. Optional boolean attribute "numbered" will cause source lines to be numbered.

Note: If c2html is not available, the region will be converted to HTML friendly text (i.e., <> turns into &lt;&gt;), and placed in a <pre> block. In this case, line numbering is not available.


Insert bookmarks at the location of the tag from the given bookmarks file. Required attribute "file" specifies which file to read from, and the optional attribute "type" may be one of: adr (for Opera), lynx, msie, ns, xbel or xmlproc. The default type is "xbel". The optional attribute "folder" may be used to specify which folder (and its children) should be inserted.

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8 Interactive Functions

emacs-wiki.el defines the following interactive functions:

— Function: emacs-wiki-edit-link-at-point

Edit the current link. Do not rename the Wiki page originally referred to.

— Function: emacs-wiki-find-file wiki command directory

Open the Emacs Wiki page wiki by name. If command is non-nil, it is the function used to visit the file. If directory is non-nil, it is the directory in which the Wiki page will be created if it does not already exist.

— Function: emacs-wiki-next-reference

Move forward to next Wiki link or URL, cycling if necessary.

— Function: emacs-wiki-previous-reference

Move backward to the next Wiki link or URL, cycling if necessary. This function is not entirely accurate, but it's close enough.

— Function: emacs-wiki-refresh-buffers &rest args

Rebuild file alist and refresh current project. Call after creating a page.

— Function: emacs-wiki-follow-name-at-point other-window

Visit the link at point, or insert a newline if none.

— Function: emacs-wiki-follow-name-at-point-other-window

Visit the link at point in other window.

— Function: emacs-wiki-follow-name-at-mouse event other-window

Visit the link at point, or yank text if none.

— Function: emacs-wiki-follow-name-at-mouse-other-window event

Visit the link at point.

— Function: emacs-wiki-rename-link-at-point

Rename the link under point, and the location it points to. This does not work with URLs, and will preserve a description in an extended link.

— Function: emacs-wiki-delete-link-at-point

Delete the link under point, and the location it points to. This does not work with URLs.

— Function: emacs-wiki-search text

Search for the given text string in the Wiki directories.

— Function: emacs-wiki-backlink

Grep for the current page name in all the Wiki directories.

— Function: emacs-wiki-index

Display an index of all known Wiki pages.

— Function: emacs-wiki-highlight-buffer

Re-highlight the entire Wiki buffer.

— Function: emacs-wiki-visit-published-file arg

Visit the current Wiki page's published result.

— Function: emacs-wiki-dired-publish

Publish all marked files in a dired buffer.

— Function: emacs-wiki-publish-index

Publish an index of the Wiki pages. This function can be added to emacs-wiki-after-wiki-publish-hook.

— Function: emacs-wiki-publish arg

Publish all Wikis that need publishing. If the published Wiki already exists, it is only overwritten if the Wiki is newer than the published copy. When given the optional argument arg, all Wikis are rewritten, no matter how recent they are. The index file is rewritten no matter what.

— Function: emacs-wiki-publish-this-page

Force publication of the current page.

— Function: emacs-wiki-change-project project

Change Wiki projects.

When called interactively, load the welcome page of the selected project in a new buffer. If no project is selected, the default project as specified in emacs-wiki-default-project will be used.

Note that the project will only be changed if the welcome page exists for the target project. This may be changed in the future to find a nonexistent file, though if this happens it is not clear which of Wiki directory should be used in the case of there being multiple directories.

When called from a Lisp program, update the current buffer's project to project.

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9 Convenience Features

The following are several miscellaneous features that might make your emacs-wiki experience more enjoyable.

Using pcomplete

If you have pcomplete loaded, you can type M-TAB to complete Wiki names. Hitting M-TAB two or more times in succession will cycle through all of the possibilities. You can find pcomplete.el in the contrib directory that comes with the emacs-wiki tarball.


If you use a ChangeLog (C-x 4 a) within one of your Wiki directories, it will be used for notifying visitors to your Wiki of recent changes.


Macros can be defined for text that you use often. Consult emacs-wiki-macros.el for information on using this feature.


This feature allows you to make custom and auto-generated navigation menus. Please consult the top of the emacs-wiki-menu.el for reasonably complete documentation.

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10 Fancy Tables

To get fancy table markup, add:

     (require 'emacs-wiki-table)

to your .emacs. In your wiki source files, you can now make tables that look like this:

      |                    A table header                                |
      |           Column 1            |           Column 2               |
      |Some text here                 |More text here, even wrapping to  |
      |                               |the next line                     |
      |Some text here                 |More text here, even wrapping to  |
      |                               |the next line                     |

See table.el for more information.

emacs-wiki-table.el does not add any interactive functions or keybindings.

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11 Multiple Projects

Emacs-wiki has a way of supporting multiple Wiki projects. This allows you to make links from one project to another, which are often called interwiki links. This can be convenient if you wish to split your website according to the kind of content, for example.

For now, it is considered good practice to have your multiple projects under a common directory, and not to nest your projects.

You will need something like the following in your .emacs file in order to set up multiple project support.

     (setq emacs-wiki-projects
           `(("WebWiki" .
              ((emacs-wiki-directories . ("~/proj/wiki/webpage"))
               (emacs-wiki-project-server-prefix . "../wiki/")
                . "~/personal-site/site/wiki")))
             ("ProjectsWiki" .
              ((emacs-wiki-directories . ("~/proj/wiki/projects"))
               (emacs-wiki-project-server-prefix . "../projects/")
                . "~/personal-site/site/projects")))))

The first phrase on the second line of code is the name of the project. In this example, there are two projects, WebWiki and ProjectsWiki. It would be best for these names to be in mixed case.

The emacs-wiki-directories line indicates which source directories correspond with the particular project. This must be a list.

emacs-wiki-project-server-prefix is the text that will be put at the beginning of each interwiki link at publish time. For example, ‘WebWiki#MyPage’ would be rendered ‘../wiki/MyPage.html’ in its published (HTML) form. It is also acceptable to give an absolute location here, like ‘/projects’, with the root directory corresponding to your root web publishing directory.

emacs-wiki-publishing-directory is the directory where the HTML content will be placed upon publishing the project. You should make sure that the content of emacs-wiki-project-server-prefix is such that a link from a file in one project to a file in another project is feasible.

Other variables can also be defined in this block if you wish to customize a particular project further.

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12 Encryption

To get PGG1 support within Emacs Wiki, add

     (require 'emacs-wiki-pgg)

to your .emacs. In your wiki source files, you can now have sections of text that is automatically encrypted when published or sections that can be decrypted/encrypted interactively.

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12.1 Interface to PGG

Make sure to set pgg-gpg-user-id to your user id. Eg:

     (setq pgg-gpg-user-id "Your user id")

There are two interfaces to PGG. This can be controlled via setting the variable emacs-wiki-pgg-interface to the correct function:

— Variable: emacs-wiki-pgg-interface
pgg-encrypt-region2 is called interactively after setting point and mark. Recipients are read from the minibuffer.
This is a personalized version of pgg-encrypt-region that is intended when the recipient is self. Message is signed if emacs-wiki-pgg-sign is non-nil. You are welcome to change pgg-encrypt-sign-self in emacs-wiki-pgg.el to suit your needs.
— Variable: emacs-wiki-pgg-sign

Set to non-nil if you want the message to be signed when the interface is pgg-encrypt-sign-self.

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12.2 gpg Tag

Enclose text that you want to encrypt/decrypt interactively in Emacs Wiki mode within these tags. Whitespace is preserved during publish via the <pre> tag.

M-x emacs-wiki-encrypt-gpg
Finds each gpg tag and encrypts the text between them using the chosen PGG interface see Interface to PGG. The resultant encrypted text is immediately visible in the buffer.
M-x emacs-wiki-decrypt-gpg
Finds each gpg tag and decrypts the text between them. The resultant decrypted text is immediately visible in the buffer.
C-u M-x emacs-wiki-encrypt-gpg
Encrypts the entire buffer using the chosen PGG interface. The resultant encrypted text is immediately visible in the buffer. The resultant wiki file is unsuitable for publishing. Use this with care.
C-u M-x emacs-wiki-decrypt-gpg
Decrypts the entire buffer. The resultant decrypted text is immediately visible.
C-c C-S-e
Calls emacs-wiki-encrypt-gpg.
C-c C-S-d
Calls emacs-wiki-decrypt-gpg.

Example: Consider the following wiki markup

     <gpg>Test data</gpg>

Press C-c C-S-e to get:

     <gpg>-----BEGIN PGP MESSAGE-----
     Version: GnuPG v1.2.4 (GNU/Linux)
     [Imagine encrypted text]
     -----END PGP MESSAGE-----

Now press C-c C-S-d to get:

     <gpg>Test data</gpg>

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12.3 gpge Tag

Enclose unencrypted text within these tags and only its encrypted version will be published to the html file. This is useful when you need to maintain an unencrypted cleartext version in your local wiki source and publish it's encrypted counterpart to your web site.


     <gpge>Test data</gpge>

Resultant html file section:

     <pre class="example">-----BEGIN PGP MESSAGE-----
     Version: GnuPG v1.2.4 (GNU/Linux)
     [Imagine encrypted text]
     -----END PGP MESSAGE-----

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13 Getting Help and Reporting Bugs

After you have read this guide, if you still have questions about EmacsWikiMode, or if you have bugs to report, there are several places you can go.

http://www.mwolson.org/projects/EmacsWiki.html is the page that Michael Olson made for emacs-wiki. For the duration of his maintainership, it may be considered the official emacs-wiki website.

You can join the mailing list at [email protected] using the subscription form at http://mail.nongnu.org/mailman/listinfo/ emacs-wiki-discuss. This mailing list is also available via Gmane (http://gmane.org/). The group is called ‘gmane.emacs.wiki.general’.

http://www.emacswiki.org/cgi-bin/wiki/EmacsWikiMode is the emacswiki.org page, and anyone may add tips and hints to it.

You can visit the IRC Freenode channel ‘#emacs’. Many of the contributors are frequently around and willing to answer your questions.

You can also contact the maintainer of EmacsWikiMode, Michael Olson, at [email protected].

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14 Contributors

     Copyright © 2001, 2002, 2003, 2004 John Wiegley
     Copyright © 2004 John Sullivan
     Copyright © 2004 Damien Elmes
     Copyright © 2004 Sacha Chua
     Copyright © 2004, 2005, 2006 Michael Olson
     Copyright © 2004 Anirudh Sasikumar
     Copyright © 2005 Yu Li

The first draft of this document was made by John Sullivan, and he did a majority of the work on it. Parts of this document were taken from the emacs-wiki.el source code, so a copyright notice for John Wiegley was added.

While Sacha Chua maintained emacs-wiki, she worked quite a bit on this document and split off the Planner and Remember sections.

Michael Olson added several sections, like the one on Multiple Projects. He also reworked some sections in various ways.

Anirudh Sasikumar contributed documentation for the Encryption node. Many thanks to him for implementing this useful feature and documenting it!

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Version 2, June 1991

     Copyright © 1989, 1991 Free Software Foundation, Inc.
     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
     Everyone is permitted to copy and distribute verbatim copies
     of this license document, but changing it is not allowed.

A.1 Preamble

The licenses for most software are designed to take away your freedom to share and change it. By contrast, the GNU General Public License is intended to guarantee your freedom to share and change free software—to make sure the software is free for all its users. This General Public License applies to most of the Free Software Foundation's software and to any other program whose authors commit to using it. (Some other Free Software Foundation software is covered by the GNU Library General Public License instead.) You can apply it to your programs, too.

When we speak of free software, we are referring to freedom, not price. Our General Public Licenses are designed to make sure that you have the freedom to distribute copies of free software (and charge for this service if you wish), that you receive source code or can get it if you want it, that you can change the software or use pieces of it in new free programs; and that you know you can do these things.

To protect your rights, we need to make restrictions that forbid anyone to deny you these rights or to ask you to surrender the rights. These restrictions translate to certain responsibilities for you if you distribute copies of the software, or if you modify it.

For example, if you distribute copies of such a program, whether gratis or for a fee, you must give the recipients all the rights that you have. You must make sure that they, too, receive or can get the source code. And you must show them these terms so they know their rights.

We protect your rights with two steps: (1) copyright the software, and (2) offer you this license which gives you legal permission to copy, distribute and/or modify the software.

Also, for each author's protection and ours, we want to make certain that everyone understands that there is no warranty for this free software. If the software is modified by someone else and passed on, we want its recipients to know that what they have is not the original, so that any problems introduced by others will not reflect on the original authors' reputations.

Finally, any free program is threatened constantly by software patents. We wish to avoid the danger that redistributors of a free program will individually obtain patent licenses, in effect making the program proprietary. To prevent this, we have made it clear that any patent must be licensed for everyone's free use or not licensed at all.

The precise terms and conditions for copying, distribution and modification follow.

  1. This License applies to any program or other work which contains a notice placed by the copyright holder saying it may be distributed under the terms of this General Public License. The “Program”, below, refers to any such program or work, and a “work based on the Program” means either the Program or any derivative work under copyright law: that is to say, a work containing the Program or a portion of it, either verbatim or with modifications and/or translated into another language. (Hereinafter, translation is included without limitation in the term “modification”.) Each licensee is addressed as “you”.

    Activities other than copying, distribution and modification are not covered by this License; they are outside its scope. The act of running the Program is not restricted, and the output from the Program is covered only if its contents constitute a work based on the Program (independent of having been made by running the Program). Whether that is true depends on what the Program does.

  2. You may copy and distribute verbatim copies of the Program's source code as you receive it, in any medium, provided that you conspicuously and appropriately publish on each copy an appropriate copyright notice and disclaimer of warranty; keep intact all the notices that refer to this License and to the absence of any warranty; and give any other recipients of the Program a copy of this License along with the Program.

    You may charge a fee for the physical act of transferring a copy, and you may at your option offer warranty protection in exchange for a fee.

  3. You may modify your copy or copies of the Program or any portion of it, thus forming a work based on the Program, and copy and distribute such modifications or work under the terms of Section 1 above, provided that you also meet all of these conditions:
    1. You must cause the modified files to carry prominent notices stating that you changed the files and the date of any change.
    2. You must cause any work that you distribute or publish, that in whole or in part contains or is derived from the Program or any part thereof, to be licensed as a whole at no charge to all third parties under the terms of this License.
    3. If the modified program normally reads commands interactively when run, you must cause it, when started running for such interactive use in the most ordinary way, to print or display an announcement including an appropriate copyright notice and a notice that there is no warranty (or else, saying that you provide a warranty) and that users may redistribute the program under these conditions, and telling the user how to view a copy of this License. (Exception: if the Program itself is interactive but does not normally print such an announcement, your work based on the Program is not required to print an announcement.)

    These requirements apply to the modified work as a whole. If identifiable sections of that work are not derived from the Program, and can be reasonably considered independent and separate works in themselves, then this License, and its terms, do not apply to those sections when you distribute them as separate works. But when you distribute the same sections as part of a whole which is a work based on the Program, the distribution of the whole must be on the terms of this License, whose permissions for other licensees extend to the entire whole, and thus to each and every part regardless of who wrote it.

    Thus, it is not the intent of this section to claim rights or contest your rights to work written entirely by you; rather, the intent is to exercise the right to control the distribution of derivative or collective works based on the Program.

    In addition, mere aggregation of another work not based on the Program with the Program (or with a work based on the Program) on a volume of a storage or distribution medium does not bring the other work under the scope of this License.

  4. You may copy and distribute the Program (or a work based on it, under Section 2) in object code or executable form under the terms of Sections 1 and 2 above provided that you also do one of the following:
    1. Accompany it with the complete corresponding machine-readable source code, which must be distributed under the terms of Sections 1 and 2 above on a medium customarily used for software interchange; or,
    2. Accompany it with a written offer, valid for at least three years, to give any third party, for a charge no more than your cost of physically performing source distribution, a complete machine-readable copy of the corresponding source code, to be distributed under the terms of Sections 1 and 2 above on a medium customarily used for software interchange; or,
    3. Accompany it with the information you received as to the offer to distribute corresponding source code. (This alternative is allowed only for noncommercial distribution and only if you received the program in object code or executable form with such an offer, in accord with Subsection b above.)

    The source code for a work means the preferred form of the work for making modifications to it. For an executable work, complete source code means all the source code for all modules it contains, plus any associated interface definition files, plus the scripts used to control compilation and installation of the executable. However, as a special exception, the source code distributed need not include anything that is normally distributed (in either source or binary form) with the major components (compiler, kernel, and so on) of the operating system on which the executable runs, unless that component itself accompanies the executable.

    If distribution of executable or object code is made by offering access to copy from a designated place, then offering equivalent access to copy the source code from the same place counts as distribution of the source code, even though third parties are not compelled to copy the source along with the object code.

  5. You may not copy, modify, sublicense, or distribute the Program except as expressly provided under this License. Any attempt otherwise to copy, modify, sublicense or distribute the Program is void, and will automatically terminate your rights under this License. However, parties who have received copies, or rights, from you under this License will not have their licenses terminated so long as such parties remain in full compliance.
  6. You are not required to accept this License, since you have not signed it. However, nothing else grants you permission to modify or distribute the Program or its derivative works. These actions are prohibited by law if you do not accept this License. Therefore, by modifying or distributing the Program (or any work based on the Program), you indicate your acceptance of this License to do so, and all its terms and conditions for copying, distributing or modifying the Program or works based on it.
  7. Each time you redistribute the Program (or any work based on the Program), the recipient automatically receives a license from the original licensor to copy, distribute or modify the Program subject to these terms and conditions. You may not impose any further restrictions on the recipients' exercise of the rights granted herein. You are not responsible for enforcing compliance by third parties to this License.
  8. If, as a consequence of a court judgment or allegation of patent infringement or for any other reason (not limited to patent issues), conditions are imposed on you (whether by court order, agreement or otherwise) that contradict the conditions of this License, they do not excuse you from the conditions of this License. If you cannot distribute so as to satisfy simultaneously your obligations under this License and any other pertinent obligations, then as a consequence you may not distribute the Program at all. For example, if a patent license would not permit royalty-free redistribution of the Program by all those who receive copies directly or indirectly through you, then the only way you could satisfy both it and this License would be to refrain entirely from distribution of the Program.

    If any portion of this section is held invalid or unenforceable under any particular circumstance, the balance of the section is intended to apply and the section as a whole is intended to apply in other circumstances.

    It is not the purpose of this section to induce you to infringe any patents or other property right claims or to contest validity of any such claims; this section has the sole purpose of protecting the integrity of the free software distribution system, which is implemented by public license practices. Many people have made generous contributions to the wide range of software distributed through that system in reliance on consistent application of that system; it is up to the author/donor to decide if he or she is willing to distribute software through any other system and a licensee cannot impose that choice.

    This section is intended to make thoroughly clear what is believed to be a consequence of the rest of this License.

  9. If the distribution and/or use of the Program is restricted in certain countries either by patents or by copyrighted interfaces, the original copyright holder who places the Program under this License may add an explicit geographical distribution limitation excluding those countries, so that distribution is permitted only in or among countries not thus excluded. In such case, this License incorporates the limitation as if written in the body of this License.
  10. The Free Software Foundation may publish revised and/or new versions of the General Public License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns.

    Each version is given a distinguishing version number. If the Program specifies a version number of this License which applies to it and “any later version”, you have the option of following the terms and conditions either of that version or of any later version published by the Free Software Foundation. If the Program does not specify a version number of this License, you may choose any version ever published by the Free Software Foundation.

  11. If you wish to incorporate parts of the Program into other free programs whose distribution conditions are different, write to the author to ask for permission. For software which is copyrighted by the Free Software Foundation, write to the Free Software Foundation; we sometimes make exceptions for this. Our decision will be guided by the two goals of preserving the free status of all derivatives of our free software and of promoting the sharing and reuse of software generally.

A.2 Appendix: How to Apply These Terms to Your New Programs

If you develop a new program, and you want it to be of the greatest possible use to the public, the best way to achieve this is to make it free software which everyone can redistribute and change under these terms.

To do so, attach the following notices to the program. It is safest to attach them to the start of each source file to most effectively convey the exclusion of warranty; and each file should have at least the “copyright” line and a pointer to where the full notice is found.

     one line to give the program's name and a brief idea of what it does.
     Copyright (C) yyyy  name of author
     This program 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 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
     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, write to the Free Software Foundation, Inc.,
     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.

Also add information on how to contact you by electronic and paper mail.

If the program is interactive, make it output a short notice like this when it starts in an interactive mode:

     Gnomovision version 69, Copyright (C) 19yy name of author
     Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
     This is free software, and you are welcome to redistribute it
     under certain conditions; type `show c' for details.

The hypothetical commands ‘show w’ and ‘show c’ should show the appropriate parts of the General Public License. Of course, the commands you use may be called something other than ‘show w’ and ‘show c’; they could even be mouse-clicks or menu items—whatever suits your program.

You should also get your employer (if you work as a programmer) or your school, if any, to sign a “copyright disclaimer” for the program, if necessary. Here is a sample; alter the names:

     Yoyodyne, Inc., hereby disclaims all copyright interest in the program
     `Gnomovision' (which makes passes at compilers) written by James Hacker.
     signature of Ty Coon, 1 April 1989
     Ty Coon, President of Vice

This General Public License does not permit incorporating your program into proprietary programs. If your program is a subroutine library, you may consider it more useful to permit linking proprietary applications with the library. If this is what you want to do, use the GNU Library General Public License instead of this License.

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[1] see Overview.

[2] A function defined by PGG