#+title: denote: Simple notes with an efficient file-naming scheme
#+author: Protesilaos Stavrou
#+email: info@protesilaos.com
#+language: en
#+options: ':t toc:nil author:t email:t num:t
#+startup: content
#+macro: stable-version 4.1.0
#+macro: release-date 2025-10-17
#+macro: development-version 4.2.0-dev
#+export_file_name: denote.texi
#+texinfo_filename: denote.info
#+texinfo_dir_category: Emacs misc features
#+texinfo_dir_title: Denote: (denote)
#+texinfo_dir_desc: Simple notes with an efficient file-naming scheme
#+texinfo_header: @set MAINTAINERSITE @uref{https://protesilaos.com,maintainer webpage}
#+texinfo_header: @set MAINTAINER Protesilaos Stavrou
#+texinfo_header: @set MAINTAINEREMAIL @email{info@protesilaos.com}
#+texinfo_header: @set MAINTAINERCONTACT @uref{mailto:info@protesilaos.com,contact the maintainer}

#+texinfo: @insertcopying

This manual, written by Protesilaos Stavrou, describes the customization
options for the Emacs package called ~denote~ (or =denote.el=), and
provides every other piece of information pertinent to it.

The documentation furnished herein corresponds to stable version
{{{stable-version}}}, released on {{{release-date}}}.  Any reference to
a newer feature which does not yet form part of the latest tagged
commit, is explicitly marked as such.

Current development target is {{{development-version}}}.

+ Package name (GNU ELPA): ~denote~
+ Official manual: <https://protesilaos.com/emacs/denote>
+ Change log: <https://protesilaos.com/emacs/denote-changelog>
+ Git repositories:
  + GitHub: <https://github.com/protesilaos/denote>
  + GitLab: <https://gitlab.com/protesilaos/denote>
+ Video demo: <https://protesilaos.com/codelog/2022-06-18-denote-demo/>
+ Backronyms: Denote Everything Neatly; Omit The Excesses.  Don't Ever
  Note Only The Epiphenomenal.

If you are viewing the README.org version of this file, please note that
the GNU ELPA machinery automatically generates an Info manual out of it.

#+toc: headlines 8 insert TOC here, with eight headline levels

* COPYING
:PROPERTIES:
:COPYING: t
:CUSTOM_ID: h:40b18bb2-4dc1-4202-bd0b-6fab535b2a0f
:END:

Copyright (C) 2022-2025  Free Software Foundation, Inc.

#+begin_quote
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3 or
any later version published by the Free Software Foundation; with no
Invariant Sections, with the Front-Cover Texts being “A GNU Manual,” and
with the Back-Cover Texts as in (a) below.  A copy of the license is
included in the section entitled “GNU Free Documentation License.”

(a) The FSF’s Back-Cover Text is: “You have the freedom to copy and
modify this GNU manual.”
#+end_quote

* Installation
:PROPERTIES:
:CUSTOM_ID: h:f3bdac2c-4704-4a51-948c-a789a2589790
:END:
#+cindex: Installation instructions

** GNU ELPA package
:PROPERTIES:
:CUSTOM_ID: h:42953f87-82bd-43ec-ab99-22b1e22955e7
:END:

The package is available as =denote=.  Simply do:

: M-x package-refresh-contents
: M-x package-install

And search for it.

GNU ELPA provides the latest stable release.  Those who prefer to follow
the development process in order to report bugs or suggest changes, can
use the version of the package from the GNU-devel ELPA archive.  Read:
https://protesilaos.com/codelog/2022-05-13-emacs-elpa-devel/.

** Manual installation
:PROPERTIES:
:CUSTOM_ID: h:d397712c-c8c0-4cfa-ad1a-ef28cf78d1f0
:END:

Assuming your Emacs files are found in =~/.emacs.d/=, execute the
following commands in a shell prompt:

#+begin_src sh
cd ~/.emacs.d

# Create a directory for manually-installed packages
mkdir manual-packages

# Go to the new directory
cd manual-packages

# Clone this repo, naming it "denote"
git clone https://github.com/protesilaos/denote denote
#+end_src

Finally, in your =init.el= (or equivalent) evaluate this:

#+begin_src emacs-lisp
;; Make Elisp files in that directory available to the user.
(add-to-list 'load-path "~/.emacs.d/manual-packages/denote")
#+end_src

Everything is in place to set up the package.

* Sample configuration
:PROPERTIES:
:CUSTOM_ID: h:5d16932d-4f7b-493d-8e6a-e5c396b15fd6
:END:
#+cindex: Package configuration

Denote is immediately useful for beginners and power users alike. This
manual covers everything in detail, though do not let the numerous
possibilities distract you from the fact that a basic configuration is
enough to be highly productive ([[#h:998ae528-9276-47ec-b642-3d7355a38f27][Get started with this sample configuration]]).

** Get started with this sample configuration
:PROPERTIES:
:CUSTOM_ID: h:998ae528-9276-47ec-b642-3d7355a38f27
:END:

If you are new to Denote, this a good configuration to get a feel for
some main features ([[#h:c54bedb4-5377-4dbd-853c-5870ace6eb33][Getting started with Denote]]). Then work your way
through the manual and expand your configuration accordingly. Only
include commands/variables that are useful to you. We provide another
code sample if you need some ideas ([[#h:58c4746b-b0d8-4896-9d88-a99b1d487231][More comprehensive sample configuration]]).

#+begin_src emacs-lisp
;; Remember that the website version of this manual shows the latest
;; developments, which may not be available in the package you are
;; using.  Instead of copying from the web site, refer to the version
;; of the documentation that comes with your package.  Evaluate:
;;
;;     (info "(denote) Sample configuration")
(use-package denote
  :ensure t
  :hook (dired-mode . denote-dired-mode)
  :bind
  (("C-c n n" . denote)
   ("C-c n r" . denote-rename-file)
   ("C-c n l" . denote-link)
   ("C-c n b" . denote-backlinks)
   ("C-c n d" . denote-dired)
   ("C-c n g" . denote-grep))
  :config
  (setq denote-directory (expand-file-name "~/Documents/notes/"))

  ;; Automatically rename Denote buffers when opening them so that
  ;; instead of their long file name they have, for example, a literal
  ;; "[D]" followed by the file's title.  Read the doc string of
  ;; `denote-rename-buffer-format' for how to modify this.
  (denote-rename-buffer-mode 1))
#+end_src

** More comprehensive sample configuration
:PROPERTIES:
:CUSTOM_ID: h:58c4746b-b0d8-4896-9d88-a99b1d487231
:END:

Here we include more of what you can configure with Denote ([[#h:998ae528-9276-47ec-b642-3d7355a38f27][Get started with this sample configuration]]).

#+begin_src emacs-lisp
;; Remember that the website version of this manual shows the latest
;; developments, which may not be available in the package you are
;; using.  Instead of copying from the web site, refer to the version
;; of the documentation that comes with your package.  Evaluate:
;;
;;     (info "(denote) Sample configuration")
(use-package denote
  :ensure t
  :hook
  ( ;; If you use Markdown or plain text files, then you want to make
   ;; the Denote links clickable (Org renders links as buttons right
   ;; away)
   (text-mode . denote-fontify-links-mode-maybe)
   ;; Apply colours to Denote names in Dired.  This applies to all
   ;; directories.  Check `denote-dired-directories' for the specific
   ;; directories you may prefer instead.  Then, instead of
   ;; `denote-dired-mode', use `denote-dired-mode-in-directories'.
   (dired-mode . denote-dired-mode))
  :bind
  ;; Denote DOES NOT define any key bindings.  This is for the user to
  ;; decide.  For example:
  ( :map global-map
    ("C-c n n" . denote)
    ("C-c n d" . denote-dired)
    ("C-c n g" . denote-grep)
    ;; If you intend to use Denote with a variety of file types, it is
    ;; easier to bind the link-related commands to the `global-map', as
    ;; shown here.  Otherwise follow the same pattern for `org-mode-map',
    ;; `markdown-mode-map', and/or `text-mode-map'.
    ("C-c n l" . denote-link)
    ("C-c n L" . denote-add-links)
    ("C-c n b" . denote-backlinks)
    ("C-c n q c" . denote-query-contents-link) ; create link that triggers a grep
    ("C-c n q f" . denote-query-filenames-link) ; create link that triggers a dired
    ;; Note that `denote-rename-file' can work from any context, not just
    ;; Dired bufffers.  That is why we bind it here to the `global-map'.
    ("C-c n r" . denote-rename-file)
    ("C-c n R" . denote-rename-file-using-front-matter)

    ;; Key bindings specifically for Dired.
    :map dired-mode-map
    ("C-c C-d C-i" . denote-dired-link-marked-notes)
    ("C-c C-d C-r" . denote-dired-rename-files)
    ("C-c C-d C-k" . denote-dired-rename-marked-files-with-keywords)
    ("C-c C-d C-R" . denote-dired-rename-marked-files-using-front-matter))

  :config
  ;; Remember to check the doc string of each of those variables.
  (setq denote-directory (expand-file-name "~/Documents/notes/"))
  (setq denote-save-buffers nil)
  (setq denote-known-keywords '("emacs" "philosophy" "politics" "economics"))
  (setq denote-infer-keywords t)
  (setq denote-sort-keywords t)
  (setq denote-prompts '(title keywords))
  (setq denote-excluded-directories-regexp nil)
  (setq denote-keywords-to-not-infer-regexp nil)
  (setq denote-rename-confirmations '(rewrite-front-matter modify-file-name))

  ;; Pick dates, where relevant, with Org's advanced interface:
  (setq denote-date-prompt-use-org-read-date t)

  ;; Automatically rename Denote buffers using the `denote-rename-buffer-format'.
  (denote-rename-buffer-mode 1))
#+end_src

* Getting started with Denote
:PROPERTIES:
:CUSTOM_ID: h:c54bedb4-5377-4dbd-853c-5870ace6eb33
:END:

At its core, Denote is a file-naming scheme ([[#h:4e9c7512-84dc-4dfb-9fa9-e15d51178e5d][The file-naming scheme]]).
It is applies to new text files that Denote creates or to existing
files of any type (videos, PDFs, images, ...). Here is the big picture
view on how to get started with Denote:

1. Create new text files with =M-x denote= ([[#h:17896c8c-d97a-4faa-abf6-31df99746ca6][Points of entry]]).
2. Rename any file anywhere with =M-x denote-rename-file=. There are
   many variations of this command, such as ~denote-dired-rename-marked-files~ ([[#h:532e8e2a-9b7d-41c0-8f4b-3c5cbb7d4dca][Renaming files]]).
3. Link to another Denote file with =M-x denote-link= ([[#h:5e5e3370-12ab-454f-ba09-88ff44214324][Add a single direct link using a file name prompt]]).
4. From any file with a Denote file name, view backlinks with =M-x
   denote-backlinks= ([[#h:c73f1f68-e214-49d5-b369-e694f6a5d708][The backlinks' buffer]]).
5. Instead of linking to a file, create a "link" to a search through
   file contents with =M-x denote-query-contents-link=. This searches
   the contents of text files in the ~denote-directory~. To only
   search against file names (not file contents!), use =M-x
   denote-query-filenames-link= ([[#h:d9a84289-2f73-4ef9-b4f0-9a0aa3e9bf0d][Add a query link]]).
6. To produce a Dired buffer with matching files and preferred
   sorting, do =M-x denote-dired= ([[#h:9fe01e63-f34f-4479-8713-f162a5ca865e][Display filtered and sorted files with ~denote-sort-dired~ or ~denote-dired~]]).
7. To search directly in the contents of your files, do =M-x
   denote-grep= ([[#h:e71c9d14-7e88-4386-91d0-9ad249947077][Use ~denote-grep~ to search inside files]]).
8. To use shorter buffer names for Denote files, enable the
   ~denote-rename-buffer-mode~ ([[#h:3ca4db16-8f26-4d7d-b748-bac48ae32d69][Automatically rename Denote file buffers]]).

There are many more features documented in this manual. Also, we have
standalone packages that provide support for Org dynamic blocks (part
of the ~denote-org~ package), fully fledged journaling with
~denote-journal~, writing of "sequence notes" with ~denote-sequence~,
and many more ([[#h:08b14682-e73f-4b11-b2e2-be3b788c8572][Packages that build on Denote]])!

* Overview
:PROPERTIES:
:CUSTOM_ID: h:a09b70a2-ae0b-4855-ac14-1dddfc8e3241
:END:

Denote aims to be a simple-to-use, focused-in-scope, and effective
note-taking and file-naming tool for Emacs.

Denote is based on the idea that files should follow a predictable and
descriptive file-naming scheme.  The file name must offer a clear
indication of what the contents are about, without reference to any
other metadata.  Denote basically streamlines the creation of such
files or file names while providing facilities to link between them
(where those files are editable).

A typical note produced by Denote looks like:

: 20240322T131856--some-title__topic1_topic2.org

Denote's file-naming scheme is not limited to "notes".  It can be used
for all types of file, including those that are not editable in Emacs,
such as videos.  Naming files in a consistent way makes their
filtering and retrieval considerably easier.  Denote provides relevant
facilities to rename files, regardless of file type.

Denote is based on the following core design principles:

+ Predictability :: File names must follow a consistent and descriptive
  naming convention ([[#h:4e9c7512-84dc-4dfb-9fa9-e15d51178e5d][The file-naming scheme]]).  The file name alone
  should offer a clear indication of what the contents are, without
  reference to any other metadatum.  This convention is not specific to
  note-taking, as it is pertinent to any form of file that is part of
  the user's long-term storage ([[#h:532e8e2a-9b7d-41c0-8f4b-3c5cbb7d4dca][Renaming files]]).

+ Composability :: Be a good Emacs citizen, by integrating with other
  packages or built-in functionality instead of re-inventing functions
  such as for filtering or greping.  The author of Denote (Protesilaos,
  aka "Prot") writes ordinary notes in plain text (=.txt=), switching on
  demand to an Org file only when its expanded set of functionality is
  required for the task at hand ([[#h:17896c8c-d97a-4faa-abf6-31df99746ca6][Points of entry]]).

+ Portability :: Notes are plain text and should remain portable.  The
  way Denote writes file names, the front matter it includes in the
  note's header, and the links it establishes must all be adequately
  usable with standard Unix tools.  No need for a database or some
  specialised software.  As Denote develops and this manual is fully
  fleshed out, there will be concrete examples on how to do the
  Denote-equivalent on the command-line.

+ Flexibility :: Do not assume the user's preference for a note-taking
  methodology.  Denote is conceptually similar to the Zettelkasten
  Method, which you can learn more about in this detailed introduction:
  <https://zettelkasten.de/introduction/>.  Notes are atomic (one file
  per note) and have a unique identifier.  However, Denote does not
  enforce a particular methodology for knowledge management, such as a
  restricted vocabulary or mutually exclusive sets of keywords.  Denote
  also does not check if the user writes thematically atomic notes.  It
  is up to the user to apply the requisite rigor and/or creativity in
  pursuit of their preferred workflow ([[#h:6060a7e6-f179-4d42-a9de-a9968aaebecc][Writing metanotes]]).

+ Hackability :: Denote's code base consists of small and reusable
  functions.  They all have documentation strings.  The idea is to make
  it easier for users of varying levels of expertise to understand what
  is going on and make surgical interventions where necessary (e.g. to
  tweak some formatting).  In this manual, we provide concrete examples
  on such user-level configurations ([[#h:4a6d92dd-19eb-4fcc-a7b5-05ce04da3a92][Keep a journal or diary]]).

Now the important part...  "Denote" is the familiar word, though it also
is a play on the "note" concept.  Plus, we can come up with acronyms,
recursive or otherwise, of increasingly dubious utility like:

+ Don't Ever Note Only The Epiphenomenal
+ Denote Everything Neatly; Omit The Excesses

But we'll let you get back to work.  Don't Eschew or Neglect your
Obligations, Tasks, and Engagements.

* Points of entry
:PROPERTIES:
:CUSTOM_ID: h:17896c8c-d97a-4faa-abf6-31df99746ca6
:END:

#+findex: denote
#+findex: denote-type
#+findex: denote-org-capture
#+findex: denote-date
#+findex: denote-subdirectory
#+findex: denote-template
#+findex: denote-signature
There are seven main ways to write a note with Denote: invoke the
~denote~, ~denote-type~, ~denote-date~, ~denote-subdirectory~,
~denote-template~, ~denote-signature~ commands, or leverage the
~org-capture-templates~ by setting up a template which calls the
function ~denote-org-capture~.  We explain all of those in the
subsequent sections.  Other more specialised commands exist as well,
which one shall learn about as they read through this manual.  We do
not want to overwhelm the user with options at this stage.

All these commands construct the file name in accordance with the user option
~denote-file-name-components-order~ ([[#h:dc8c40e0-233a-4991-9ad3-2cf5f05ef1cd][Change the order of file name components]]).

** Standard note creation
:PROPERTIES:
:CUSTOM_ID: h:6a92a8b5-d766-42cc-8e5b-8dc255466a23
:END:

The ~denote~ command will prompt for a title.  If a region is active,
the text of the region becomes the default at the minibuffer prompt
(meaning that typing =RET= without any input will use the default
value).  Once the title is supplied, the ~denote~ command will then ask
for keywords.  The resulting note will have a file name as already
explained: [[#h:4e9c7512-84dc-4dfb-9fa9-e15d51178e5d][The file naming scheme]]

#+vindex: denote-after-new-note-hook
The ~denote~ command runs the hook ~denote-after-new-note-hook~ after
creating the new note ([[#h:a947908e-1847-4471-ba07-377ee2f4b36c][Access the data of the latest note]]). When
called from Lisp, it returns the path it generates. Before returning
the path, it decides what to do with the buffer of the note, in
accordance with the user option ~denote-kill-buffers~ ([[#h:c8fd826f-3ac9-4820-9709-4375603f8865][The ~denote-kill-buffers~ option]]).

The file type of the new note is determined by the user option
~denote-file-type~ ([[#h:13218826-56a5-482a-9b91-5b6de4f14261][Front matter]]).

#+vindex: denote-known-keywords
#+vindex: denote-infer-keywords
The keywords' prompt supports minibuffer completion.  Available
candidates are those defined in the user option ~denote-known-keywords~.
More candidates can be inferred from the names of existing notes, by
setting ~denote-infer-keywords~ to non-nil (which is the case by
default) ([[#h:c0fb477f-4f99-4d76-9cce-132bcfcb351d][Create a controlled vocabulary for keywords]]).

#+vindex: denote-sort-keywords
Multiple keywords can be inserted by separating them with a comma (or
whatever the value of the ~crm-separator~ is---which should be a comma).
When the user option ~denote-sort-keywords~ is non-nil (the default),
keywords are sorted alphabetically (technically, the sorting is done
with ~string-lessp~).

The interactive behaviour of the ~denote~ command is influenced by the
user option ~denote-prompts~ ([[#h:f9204f1f-fcee-49b1-8081-16a08a338099][The denote-prompts option]]).

The ~denote~ command can also be called from Lisp.  Read its doc string
for the technicalities.

#+findex: denote-create-note
In the interest of discoverability, ~denote~ is also available under the
alias ~denote-create-note~.

*** The ~denote-directory~ option
:PROPERTIES:
:CUSTOM_ID: h:e2809afb-5c6c-4a20-9881-00c987bb5345
:END:

#+vindex: denote-directory
The Denote file-naming scheme can be applied to any file anywhere on
the file system ([[#h:532e8e2a-9b7d-41c0-8f4b-3c5cbb7d4dca][Renaming files]]). Still, Denote needs a dedicated
directory to store the files it creates. To this end, the user option
~denote-directory~ specifies the directory, as a string, where new
files are created ([[#h:6a92a8b5-d766-42cc-8e5b-8dc255466a23][Standard note creation]]).

The default path is =~/Documents/notes/=. If the directory does not
exist, Denote will create it upon generating a new note.

The ~denote-directory~ is consulted by Denote commands that operate on
existing files, such as the linking mechanism and the search mechanism:

- [[#h:fc913d54-26c8-4c41-be86-999839e8ad31][Linking notes]]
- [[#h:e71c9d14-7e88-4386-91d0-9ad249947077][Use ~denote-grep~ to search inside files]]

In general, any command that needs to operate on existing Denote files
is expected to rely on the ~denote-directory~.

The value of ~denote-directory~ may also be a list of strings, each
pointing to a file system path. This allows users to maintain distinct
directories that can still be considered part of the same continuum,
as opposed to silos ([[#h:15719799-a5ff-4e9a-9f10-4ca03ef8f6c5][Maintain separate directory silos for notes]]).
Denote commands will otherwise behave the same way.

Users who choose to set ~denote-directory~ to a list of directories
may also want to include a directory prompt when creating new files
([[#h:f9204f1f-fcee-49b1-8081-16a08a338099][The ~denote-prompts~ option]]).

*** The ~denote-prompts~ option
:PROPERTIES:
:CUSTOM_ID: h:f9204f1f-fcee-49b1-8081-16a08a338099
:END:

#+vindex: denote-prompts
The user option ~denote-prompts~ determines how the ~denote~ command
will behave interactively ([[#h:6a92a8b5-d766-42cc-8e5b-8dc255466a23][Standard note creation]]).

Commands that prompt for user input to construct a Denote file name
include, but are not limited to: ~denote~, ~denote-signature~,
~denote-type~, ~denote-date~, ~denote-subdirectory~,
~denote-rename-file~, ~denote-dired-rename-files~.

- [[#h:887bdced-9686-4e80-906f-789e407f2e8f][Convenience commands for note creation]].
- [[#h:532e8e2a-9b7d-41c0-8f4b-3c5cbb7d4dca][Renaming files]].

The value of this user option is a list of symbols, which includes any
of the following:

- =title=: Prompt for the title of the new note ([[#h:403422a7-7578-494b-8f33-813874c12da3][The ~denote-history-completion-in-prompts~ option]]).

- =keywords=: Prompts with completion for the keywords of the new note.
  Available candidates are those specified in the user option
  ~denote-known-keywords~.  If the user option ~denote-infer-keywords~
  is non-nil, keywords in existing note file names are included in the
  list of candidates.  The =keywords= prompt uses
  ~completing-read-multiple~, meaning that it can accept multiple
  keywords separated by a comma (or whatever the value of ~crm-separator~
  is).

- =file-type=: Prompts with completion for the file type of the new
  note.  Available candidates are those specified in the user option
  ~denote-file-type~.  Without this prompt, ~denote~ uses the value of
  ~denote-file-type~.

- =subdirectory=: Prompts with completion for a directory or
  subdirectory in which to create the note. Available candidates are
  the value of the user option ~denote-directory~ and all of its
  subdirectories ([[#h:e2809afb-5c6c-4a20-9881-00c987bb5345][The ~denote-directory~ option]]). Any subdirectory
  must already exist: Denote will not create it.

- =date=: Prompts for the date of the new note.  It will expect an input
  like 2022-06-16 or a date plus time: 2022-06-16 14:30.  Without the
  =date= prompt, the ~denote~ command uses the ~current-time~.

  [[#h:e7ef08d6-af1b-4ab3-bb00-494a653e6d63][The denote-date-prompt-use-org-read-date option]].

- =identifier=: Prompts with completion for the identifier of the new
  note. It expects a string that has the format of ~denote-date-identifier-format~.
  [ Also see: [[#h:197f83af-6149-4262-a186-14d0eab24f1e][A custom identifier that is a simple string given at the prompt each time]]. ]

- =template=: Prompts for a KEY among the ~denote-templates~.  The value
  of that KEY is used to populate the new note with content, which is
  added after the front matter ([[#h:f635a490-d29e-4608-9372-7bd13b34d56c][The denote-templates option]]).

- =signature=: - Prompts for an arbitrary string that can be used for
  any kind of workflow, such as a special tag to label the =part1= and
  =part2= of a large file that is split in half, or to add special
  contexts like =home= and =work=, or even priorities like =a=, =b=,
  =c=. One other use-case is to implement a sequencing scheme that
  makes notes have hierarchical relationships. This is handled by our
  optional extension =denote-sequence.el=, which is part of the
  ~denote~ package ([[#h:d5ca722d-e7fa-46fa-9a57-6363b1d4186f][Write sequence notes or "folgezettel"]]).

The prompts occur in the given order.

If the value of this user option is nil, no prompts are used.  The
resulting file name will consist of an identifier (i.e. the date and
time) and a supported file type extension (per ~denote-file-type~).

Recall that Denote's standard file-naming scheme is defined as follows
([[#h:4e9c7512-84dc-4dfb-9fa9-e15d51178e5d][The file-naming scheme]]):

: ID--TITLE__KEYWORDS.EXT

If either or both of the =title= and =keywords= prompts are not
included in the value of this variable, file names will be any of
those permutations:

: ID.EXT
: ID--TITLE.EXT
: ID__KEYWORDS.EXT

When in doubt, always include the =title= and =keywords= prompts.

Finally, this user option only affects the interactive use of the
~denote~ or other relevant commands (advanced users can call it from
Lisp). In Lisp usage, the behaviour is always what the caller
specifies, based on the supplied arguments.

*** The ~denote-history-completion-in-prompts~ option
:PROPERTIES:
:CUSTOM_ID: h:403422a7-7578-494b-8f33-813874c12da3
:END:

#+vindex: denote-history-completion-in-prompts
The user option ~denote-history-completion-in-prompts~ toggles history
completion in all ~denote-prompts-with-history-as-completion~.

When this user option is set to a non-nil value, Denote will use
minibuffer history entries as completion candidates in all of the
~denote-prompts-with-history-as-completion~. Those will show previous
inputs from their respective history as possible values to select,
either to (i) re-insert them verbatim or (ii) with the intent to edit
them further (depending on the minibuffer user interface, one can
select a candidate with =TAB= without exiting the minibuffer, as
opposed to what =RET= normally does by selecting and exiting).

When this user option is set to a nil value, all of the
~denote-prompts-with-history-as-completion~ will not use minibuffer
completion: they will just prompt for a string of characters. Their
history is still available through all the standard ways of retrieving
minibuffer history, such as with the command ~previous-history-element~.

History completion still allows arbitrary values to be provided as
input: they do not have to match the available minibuffer completion
candidates.

Note that some prompts, like ~denote-keywords-prompt~, always use
minibuffer completion, due to the specifics of their data.

[ Consider enabling the built-in ~savehist-mode~ to persist minibuffer
  histories between sessions.]

*** The ~denote-templates~ option
:PROPERTIES:
:CUSTOM_ID: h:f635a490-d29e-4608-9372-7bd13b34d56c
:END:

#+vindex: denote-templates
The user option ~denote-templates~ is an alist of content templates for
new notes.  A template is arbitrary text that Denote will add to a newly
created note right below the front matter.

Templates are expressed as a =(KEY . VALUE)= association.

- The =KEY= is the name which identifies the template.  It is an
  arbitrary symbol, such as =report=, =memo=, =statement=.

- The =VALUE= is either a string or the symbol of a function.

  - If it is a string, it is ordinary text that Denote will insert
    as-is.  It can contain newline characters to add spacing.  The
    manual of Denote contains examples on how to use the ~concat~
    function, beside writing a generic string.

  - If it is a function, it is called without arguments and is expected
    to return a string.  Denote will call the function and insert the
    result in the buffer.

The user can choose a template either by invoking the command
~denote-template~ or by changing the user option ~denote-prompts~ to
always prompt for a template when calling the ~denote~ command.

[[#h:f9204f1f-fcee-49b1-8081-16a08a338099][The denote-prompts option]].

[[#h:887bdced-9686-4e80-906f-789e407f2e8f][Convenience commands for note creation]].

Templates can be written directly as one large string.  For example (the
=\n= character is read as a newline):

#+begin_src emacs-lisp
(setq denote-templates
      '((report . "* Some heading\n\n* Another heading")
        (memo . "* Some heading

,* Another heading

")))
#+end_src

Long strings may be easier to type but interpret indentation literally.
Also, they do not scale well.  A better way is to use some Elisp code to
construct the string.  This would typically be the ~concat~ function,
which joins multiple strings into one.  The following is the same as the
previous example:

#+begin_src emacs-lisp
(setq denote-templates
      `((report . "* Some heading\n\n* Another heading")
        (memo . ,(concat "* Some heading"
                         "\n\n"
                         "* Another heading"
                         "\n\n"))))
#+end_src

Notice that to evaluate a function inside of an alist we use the
backtick to quote the alist (NOT the straight quote) and then prepend a
comma to the expression that should be evaluated.  The ~concat~ form
here is not sensitive to indentation, so it is easier to adjust for
legibility.

For when the =VALUE= is a function, we have this:

#+begin_src emacs-lisp
(setq denote-templates
      `((report . "* Some heading\n\n* Another heading")
        (blog . my-denote-template-function-for-blog) ; a function to return a string
        (memo . ,(concat "* Some heading"
                         "\n\n"
                         "* Another heading"
                         "\n\n"))))
#+end_src

In this example, ~my-denote-template-function-for-blog~ is a function
that returns a string. Denote will take care to insert it in the buffer.

DEV NOTE: We do not provide more examples at this point, though feel
welcome to ask for help if the information provided herein is not
sufficient.  We shall expand the manual accordingly.

*** Convenience commands for note creation
:PROPERTIES:
:CUSTOM_ID: h:887bdced-9686-4e80-906f-789e407f2e8f
:END:

Sometimes the user needs to create a note that has different
requirements from those of ~denote~ ([[#h:6a92a8b5-d766-42cc-8e5b-8dc255466a23][Standard note creation]]).  While
this can be achieved globally by changing the ~denote-prompts~ user
option, there are cases where an ad-hoc method is the appropriate one
([[#h:f9204f1f-fcee-49b1-8081-16a08a338099][The denote-prompts option]]).

To this end, Denote provides the following interactive convenience
commands for note creation. They all work by appending a new prompt to
the existing ~denote-prompts~.

+ Create note by specifying file type :: The ~denote-type~ command
  creates a note while prompting for a file type.

  This is the equivalent of calling ~denote~ when ~denote-prompts~ has
  the =file-type= prompt appended to its existing prompts. In practical
  terms, this lets you produce, say, a note in Markdown even though
  you normally write in Org ([[#h:6a92a8b5-d766-42cc-8e5b-8dc255466a23][Standard note creation]]).

  #+findex: denote-create-note-using-type
  The ~denote-create-note-using-type~ is an alias of ~denote-type~.

+ Create note using a date :: Normally, Denote reads the current date
  and time to construct the unique identifier of a newly created note
  ([[#h:6a92a8b5-d766-42cc-8e5b-8dc255466a23][Standard note creation]]).  Sometimes, however, the user needs to set
  an explicit date+time value.

  This is where the ~denote-date~ command comes in.  It creates a note
  while prompting for a date.  The date can be in YEAR-MONTH-DAY
  notation like =2022-06-30= or that plus the time: =2022-06-16 14:30=.

  [[#h:e7ef08d6-af1b-4ab3-bb00-494a653e6d63][The denote-date-prompt-use-org-read-date option]].

  This is the equivalent of calling ~denote~ when ~denote-prompts~ has
  the =date= prompt appended to its existing prompts.

  #+findex: denote-create-note-using-date
  The ~denote-create-note-using-date~ is an alias of ~denote-date~.

+ Create note in a specific directory :: The ~denote-subdirectory~
  command creates a note while prompting for a subdirectory.  Available
  candidates include the value of the variable ~denote-directory~ and
  any subdirectory thereof (Denote does not create subdirectories).

  This is the equivalent of calling ~denote~ when ~denote-prompts~ has
  the =subdirectory= prompt appended to its existing prompts.

  #+findex: denote-create-note-in-subdirectory
  The ~denote-create-note-in-subdirectory~ is a more descriptive alias
  of ~denote-subdirectory~.

+ Create note and add a template :: The ~denote-template~ command
  creates a new note and inserts the specified template below the front
  matter ([[#h:f635a490-d29e-4608-9372-7bd13b34d56c][The denote-templates option]]).  Available candidates for
  templates are specified in the user option ~denote-templates~.

  This is the equivalent of calling ~denote~ when ~denote-prompts~ has
  the =template= prompt appended to its existing prompts.

  #+findex: denote-create-note-with-template
  The ~denote-create-note-with-template~ is an alias of the command
  ~denote-template~, meant to help with discoverability.

+ Create note with a signature :: The ~denote-signature~ command first
  prompts for an arbitrary string to use in the optional =SIGNATURE=
  field of the file name and then asks for a title and keywords.
  Signatures are arbitrary strings of alphanumeric characters which
  can be used to establish sequential relations between file at the
  level of their file name (e.g. 1, 1a, 1b, 1b1, 1b2, ...).

  This is the equivalent of calling ~denote~ when ~denote-prompts~ has
  the =signature= prompt appended to its existing prompts.

  The ~denote-create-note-using-signature~ is an alias of the command
  ~denote-signature~ intended to make the functionality more
  discoverable.

**** Write your own convenience commands
:PROPERTIES:
:CUSTOM_ID: h:11946562-7eb0-4925-a3b5-92d75f1f5895
:END:

The convenience commands we provide only cover some basic use-cases
([[#h:887bdced-9686-4e80-906f-789e407f2e8f][Convenience commands for note creation]]). The user may require
combinations that are not covered, such as to prompt for a template
and for a subdirectory, instead of only one of the two. To this end,
we show how to follow the code we use in Denote to write your own
variants of those commands.

First let's take a look at the definition of one of those commands.
They all look the same, but we use ~denote-subdirectory~ for this
example:

#+begin_src emacs-lisp
(defun denote-subdirectory ()
  "Create note while prompting for a subdirectory.

Available candidates include the value of the variable
`denote-directory' and any subdirectory thereof.

This is the equivalent of calling `denote' when `denote-prompts'
has the `subdirectory' prompt appended to its existing prompts."
  (declare (interactive-only t))
  (interactive)
  (let ((denote-prompts (denote-add-prompts '(subdirectory))))
    (call-interactively #'denote)))
#+end_src

The hyphenated word after ~defun~ is the name of the function. It has
to be unique. Then we have the documentation string (or "doc string")
which is for the user's convenience.

This function is ~interactive~, meaning that it can be called via
=M-x= or be assigned to a key binding. Then we have the local binding
of the ~denote-prompts~ to the desired combination ("local" means
specific to this function without affecting other contexts). Lastly,
it calls the standard ~denote~ command interactively, so it uses all
the prompts in their specified order.

The function call ~(denote-add-prompts '(subdirectory))~ will append
the subdirectory prompt to the existing value of the ~denote-prompts~.
If, for example, the default value is ='(title keywords)= (to prompt
for a title and then for keywords), it will become ='(subdirectory
title keywords)= inside the context of this ~let~. Remember that this
is "local", so the global value of ~denote-prompts~ remains unaffected.

Now let's say we want to have a command that (i) asks for a template
(ii) for a subdirectory ([[#h:f635a490-d29e-4608-9372-7bd13b34d56c][The denote-templates option]]), and (iii) then
goes through the remaining ~denote-prompts~. All we need to do is
tweak the ~let~ bound value of ~denote-prompts~ and give our command a
unique name:

#+begin_src emacs-lisp
;; Like `denote-subdirectory' but also ask for a template
(defun my-denote-subdirectory-with-template ()
  "Create note while also prompting for a template and subdirectory.

This is the equivalent of calling `denote' when `denote-prompts' has the
`subdirectory' and `template' prompts appended to its existing prompts."
  (declare (interactive-only t))
  (interactive)
  (let ((denote-prompts (denote-add-prompts '(subdirectory template))))
    (call-interactively #'denote)))
#+end_src

The tweaks to ~denote-prompts~ determine how the command will behave
([[#h:f9204f1f-fcee-49b1-8081-16a08a338099][The denote-prompts option]]). Use this paradigm to write your own
variants which you can then assign to keys, invoke with =M-x=, or add
to the list of commands available at the ~denote-command-prompt~
([[#h:98c732ac-da0e-4ebd-a0e3-5c47f9075e51][Choose which commands to prompt for]]).

In the above scenario, we are using the ~denote-add-prompts~ function,
which appends whatever prompts we want to the existing value of
~denote-prompts~. If the user prefers to completely override the
~denote-prompts~, they can set the value outright:

#+begin_src emacs-lisp
(defun my-denote-subdirectory-with-template-title-and-keywords ()
  "Create a note while prompting for subdirectory, template, title, and keywords.

This is the equivalent of calling `denote' when `denote-prompts' has the
value '(template subdirectory title keywords)."
  (declare (interactive-only t))
  (interactive)
  (let ((denote-prompts '(subdirectory template title keywords)))
    (call-interactively #'denote)))
#+end_src

*** The ~denote-save-buffers~ option
:PROPERTIES:
:CUSTOM_ID: h:bf80f4cd-6f56-4f7c-a991-8573161e4511
:END:

#+vindex: denote-save-buffers
The user option ~denote-save-buffers~ controls whether commands that
create new notes ([[#h:17896c8c-d97a-4faa-abf6-31df99746ca6][Points of entry]]) or rename existing files save their
buffer outright ([[#h:532e8e2a-9b7d-41c0-8f4b-3c5cbb7d4dca][Renaming files]]). By default, when the value of this
user option is ~nil~, buffers are not saved. They are saved when the
value is non-~nil~.

[[#h:c8fd826f-3ac9-4820-9709-4375603f8865][The ~denote-kill-buffers~ option]].

*** The ~denote-kill-buffers~ option
:PROPERTIES:
:CUSTOM_ID: h:c8fd826f-3ac9-4820-9709-4375603f8865
:END:

#+vindex: denote-kill-buffers
The user option ~denote-kill-buffers~ controls whether to kill a
buffer that was generated by a Denote command. This can happen when
creating a new file or renaming an existing one.

- [[#h:17896c8c-d97a-4faa-abf6-31df99746ca6][Points of entry]].
- [[#h:532e8e2a-9b7d-41c0-8f4b-3c5cbb7d4dca][Renaming files]].

The default behaviour of creation or renaming commands such as
~denote~ and ~denote-rename-file~ is to not kill the buffer they
create or modify at the end of their operation. The idea is to give
the user the chance to confirm that everything is in order.

If this user option is nil (the default), buffers affected by a
creation or renaming command are not automatically killed.

If set to the symbol =on-creation=, new notes are automatically killed.

If set to the symbol =on-rename=, renamed notes are automatically killed.

If set to t, new and renamed notes are killed.

If a buffer is killed, it is also saved, as if ~denote-save-buffers~
were set to a non-~nil~ value ([[#h:bf80f4cd-6f56-4f7c-a991-8573161e4511][The ~denote-save-buffers~ option]]).

In all cases, if the buffer already existed before the Denote operation
it is NOT automatically killed.

*** The ~denote-date-prompt-use-org-read-date~ option
:PROPERTIES:
:CUSTOM_ID: h:e7ef08d6-af1b-4ab3-bb00-494a653e6d63
:END:

By default, Denote uses its own simple prompt for date or date+time
input ([[#h:f9204f1f-fcee-49b1-8081-16a08a338099][The denote-prompts option]]).  This is done when the
~denote-prompts~ option includes a =date= symbol and/or when the user
invokes the ~denote-date~ command.

#+vindex: denote-date-prompt-use-org-read-date
Users who want to benefit from the more advanced date selection method
that is common in interactions with Org mode, can set the user option
~denote-date-prompt-use-org-read-date~ to a non-nil value.


** Create note using Org capture
:PROPERTIES:
:CUSTOM_ID: h:656c70cd-cf9a-4471-a0b5-4f0aaf60f881
:END:

For integration with ~org-capture~, the user must first add the relevant
template.  Such as:

#+begin_src emacs-lisp
(with-eval-after-load 'org-capture
  (add-to-list 'org-capture-templates
               '("n" "New note (with Denote)" plain
                 (file denote-last-path)
                 #'denote-org-capture
                 :no-save t
                 :immediate-finish nil
                 :kill-buffer t
                 :jump-to-captured t)))
#+end_src

Once the template is added, it is accessed from the specified key. If,
for instance, ~org-capture~ is bound to =C-c c=, then the note
creation is initiated with =C-c c n=, per the above snippet. After
that, the process is the same as with invoking ~denote~ directly,
namely: a prompt for a title followed by a prompt for keywords,
assuming the default settings ([[#h:6a92a8b5-d766-42cc-8e5b-8dc255466a23][Standard note creation]]). Concretely,
this method always respects the value of the user option
~denote-prompts~ ([[#h:f9204f1f-fcee-49b1-8081-16a08a338099][The ~denote-prompts~ option]]).

It is also possible to define templates that have specific prompts or
certain values set, for which there is no prompt:

- [[#h:115b6797-f265-40e9-a603-32eeda13a7ac][Create note with specific values using Org capture]]
- [[#h:95b78582-9086-47e8-967f-62373e2369a0][Create note with specific prompts using Org capture]]

#+vindex: denote-org-capture-specifiers
Users may prefer to leverage ~org-capture~ in order to extend file
creation with the specifiers described in the ~org-capture-templates~
documentation (such as to capture the active region and/or create a
hyperlink pointing to the given context).

IMPORTANT.  Due to the particular file-naming scheme of Denote, which is
derived dynamically, such specifiers or other arbitrary text cannot be
written directly in the template.  Instead, they have to be assigned to
the user option ~denote-org-capture-specifiers~, which is interpreted by
the function ~denote-org-capture~.  Example with our default value:

#+begin_src emacs-lisp
(setq denote-org-capture-specifiers "%l\n%i\n%?")
#+end_src

Note that ~denote-org-capture~ ignores the ~denote-file-type~: it always
sets the Org file extension for the created note to ensure that the
capture process works as intended, especially for the desired output of
the ~denote-org-capture-specifiers~.

Developers or advanced users who ~let~ bind the ~denote-use-template~
must consider setting ~denote-org-capture-specifiers~ to nil or an
appropriate string ([[#h:a8b9082c-8bd5-492d-8da7-4f41ee493d59][Predefined note values for developers or advanced users]]).
Otherwise the contents of the new note may contain duplicates.

[ You may not need ~org-capture~ to do what you want ([[#h:11946562-7eb0-4925-a3b5-92d75f1f5895][Write your own convenience commands]]). ]

** Create note with specific prompts using Org capture
:PROPERTIES:
:CUSTOM_ID: h:95b78582-9086-47e8-967f-62373e2369a0
:END:

This section assumes knowledge of how Denote+org-capture work, as
explained in the previous section ([[#h:656c70cd-cf9a-4471-a0b5-4f0aaf60f881][Create note using Org capture]]).

#+findex: denote-org-capture-with-prompts
The previous section shows how to define an Org capture template that
always prompts for whatever is set in the user option ~denote-prompts~
(title and keywords, by default). There are, however, cases where the
user wants more control over what kind of input Denote will prompt
for. To this end, we provide the function ~denote-org-capture-with-prompts~.
Below we explain it and then show some examples of how to use it.

The ~denote-org-capture-with-prompts~ is like ~denote-org-capture~ but
with optional prompt parameters.

When called without arguments, it does not prompt for anything.  It
just returns the front matter with title and keyword fields empty and
the date and identifier fields specified.  It also makes the file name
consist of only the identifier plus the Org file name extension ([[#h:4e9c7512-84dc-4dfb-9fa9-e15d51178e5d][The file-naming scheme]]).

Otherwise, it produces a minibuffer prompt for every non-nil value
that corresponds to the =TITLE=, =KEYWORDS=, =SUBDIRECTORY=, =DATE=,
and =TEMPLATE= arguments.  The prompts are those used by the standard
~denote~ command and all of its utility commands ([[#h:17896c8c-d97a-4faa-abf6-31df99746ca6][Points of entry]]).

When returning the contents that fill in the Org capture template, the
sequence is as follows: front matter, =TEMPLATE=, and then the value
of the user option ~denote-org-capture-specifiers~.

Important note: in the case of =SUBDIRECTORY= actual subdirectories
must exist---Denote does not create them.  Same principle for
=TEMPLATE= as templates must exist and are specified in the user
option ~denote-templates~.

This is how one can incorporate ~denote-org-capture-with-prompts~ in
their Org capture templates.  Instead of passing a generic ~t~ which
makes it hard to remember what the argument means, we use semantic
keywords like =:title= for our convenience (internally this does not
matter as the value still counts as non-nil, so =:foo= for =TITLE= is
treated the same as =:title= or ~t~).

#+begin_src emacs-lisp
;; This prompts for TITLE, KEYWORDS, and SUBDIRECTORY
(add-to-list 'org-capture-templates
             '("N" "New note with prompts (with denote.el)" plain
               (file denote-last-path)
               (function
                (lambda ()
                  (denote-org-capture-with-prompts :title :keywords :subdirectory)))
               :no-save t
               :immediate-finish nil
               :kill-buffer t
               :jump-to-captured t))

;; This prompts only for SUBDIRECTORY
(add-to-list 'org-capture-templates
             '("N" "New note with prompts (with denote.el)" plain
               (file denote-last-path)
               (function
                (lambda ()
                  (denote-org-capture-with-prompts nil nil :subdirectory)))
               :no-save t
               :immediate-finish nil
               :kill-buffer t
               :jump-to-captured t))

;; This prompts for TITLE and SUBDIRECTORY
(add-to-list 'org-capture-templates
             '("N" "New note with prompts (with denote.el)" plain
               (file denote-last-path)
               (function
                (lambda ()
                  (denote-org-capture-with-prompts :title nil :subdirectory)))
               :no-save t
               :immediate-finish nil
               :kill-buffer t
               :jump-to-captured t))
#+end_src

[ You may not need ~org-capture~ to do what you want ([[#h:11946562-7eb0-4925-a3b5-92d75f1f5895][Write your own convenience commands]]). ]

** Create note with specific values using Org capture
:PROPERTIES:
:CUSTOM_ID: h:115b6797-f265-40e9-a603-32eeda13a7ac
:END:

The ordinary procedure to create a note with ~org-capture~ respects
the value of the user option ~denote-prompts~ ([[#h:656c70cd-cf9a-4471-a0b5-4f0aaf60f881][Create note using Org capture]]):
the user is prompted for all the values they have configured (title
and keywords, by default). Sometimes, there is no need to have a
certain prompt because the value of it will be constant. For example,
the user wants to have a template that (i) respects the
~denote-prompts~ but (ii) puts the new note in an existing subdirectory
of the ~denote-directory~. The following code block does exactly that.

[ It also is possible to have a template that deviates from
  ~denote-prompts~ and prompts for specific values ([[#h:95b78582-9086-47e8-967f-62373e2369a0][Create note with specific prompts using Org capture]]). ]

#+begin_src emacs-lisp
(with-eval-after-load 'org-capture
  (add-to-list 'org-capture-templates
               '("r" "New reference (with Denote)" plain
                 (file denote-last-path)
                 (function
                  (lambda ()
                    (let ((denote-use-directory (expand-file-name "reference" (denote-directory))))
                      (denote-org-capture))))
                 :no-save t
                 :immediate-finish nil
                 :kill-buffer t
                 :jump-to-captured t)))
#+end_src

The values one may predefine in this way are described elsewhere in
this manual ([[#h:a8b9082c-8bd5-492d-8da7-4f41ee493d59][Predefined note values for developers or advanced users]]).
When there exists a binding for those variables, the corresponding
prompt is always skipped. It is thus paramount to never set those
variables outside the scope of a ~let~ (or equivalent).

With those granted, here is another example scenario where the user
wants to have a constant value for the subdirectory but also be
prompted for a date.

#+begin_src emacs-lisp
(with-eval-after-load 'org-capture
  (add-to-list 'org-capture-templates
               '("j" "New journal (with Denote)" plain
                 (file denote-last-path)
                 (function
                  (lambda ()
                    ;; The "journal" subdirectory of the `denote-directory'---this must exist!
                    (let* ((denote-use-directory (expand-file-name "journal" (denote-directory)))
                           ;; Use the existing `denote-prompts' as well as the one for a date.
                           (denote-prompts (denote-add-prompts '(date))))
                      (denote-org-capture))))
                 :no-save t
                 :immediate-finish nil
                 :kill-buffer t
                 :jump-to-captured t)))
#+end_src

The above highlights the hackability of the Denote code base, namely,
how we can affect the behaviour of the underlying ~denote~ command by
~let~ binding variables that affect every aspect of its behaviour
([[#h:11946562-7eb0-4925-a3b5-92d75f1f5895][Write your own convenience commands]]).


** Create a note with the region's contents
:PROPERTIES:
:CUSTOM_ID: h:2f8090f1-50af-4965-9771-d5a91a0a87bd
:END:

#+findex: denote-region
The command ~denote-region~ takes the contents of the active region
and then calls the ~denote~ command.  Once a new note is created, it
inserts the contents of the region therein.  This is useful to
quickly elaborate on some snippet of text or capture it for future
reference.

#+vindex: denote-region-after-new-note-functions
When the ~denote-region~ command is called with an active region, it
finalises its work by calling ~denote-region-after-new-note-functions~.
This is an abnormal hook, meaning that the functions added to it are
called with arguments.  The arguments are two, representing the
beginning and end positions of the newly inserted text.

A common use-case for Org mode users is to call the command
~org-insert-structure-template~ after a region is inserted.  Emacs
will thus prompt for a structure template, such as the one
corresponding to a source block.  In this case the function added to
~denote-region-after-new-note-functions~ does not actually need
aforementioned arguments: it can simply declare those as ignored by
prefixing the argument names with an underscore (an underscore is
enough, but it is better to include a name for clarity).  For example,
the following will prompt for a structure template as soon as
~denote-region~ is done:

#+begin_src emacs-lisp
(defun my-denote-region-org-structure-template (_beg _end)
  (when (derived-mode-p 'org-mode)
    (activate-mark)
    (call-interactively 'org-insert-structure-template)))

(add-hook 'denote-region-after-new-note-functions #'my-denote-region-org-structure-template)
#+end_src

Remember that ~denote-region-after-new-note-functions~ are not called
if ~denote-region~ is used without an active region.

*** A custom ~denote-region~ that references the source
:PROPERTIES:
:CUSTOM_ID: h:eb72086e-05be-4ae3-af51-7616999fc7c9
:END:

The ~denote-region~ command simply creates a new note and includes the
highlighted region's contents as the initial text of the note ([[#h:2f8090f1-50af-4965-9771-d5a91a0a87bd][Create a note with the region's contents]]).
However, users may want a more streamlined workflow where the command
is always used to capture quotes from other sources. In this example,
we consider "other sources" to come from Emacs EWW buffers (with ~M-x
eww~) or regular files outside the ~denote-directory~.

[ This is a proof-of-concept that does not cover all cases. If anyone
  wants to use a variation of this, just let me know. ]

#+begin_src emacs-lisp
;; Variant of `my-denote-region' to reference the source

(defun my-denote-region-get-source-reference ()
  "Get a reference to the source for use with `my-denote-region'.
The reference is a URL or an Org-formatted link to a file."
  ;; We use a `cond' here because we can extend it to cover move
  ;; cases.
  (cond
   ((derived-mode-p 'eww-mode)
    (plist-get eww-data :url))
   ;; Here we are just assuming an Org format.  We can make this more
   ;; involved, if needed.
   (buffer-file-name
    (format "[[file:%s][%s]]" buffer-file-name (buffer-name)))))

(defun my-denote-region ()
  "Like `denote-region', but add the context afterwards.
For how the context is retrieved, see `my-denote-region-get-source-reference'."
  (interactive)
  (let ((context (my-denote-region-get-source-reference)))
    (call-interactively 'denote-region)
    (when context
      (goto-char (point-max))
      (insert "\n")
      (insert context))))

;; Add quotes around snippets of text captured with `denote-region' or `my-denote-region'.

(defun my-denote-region-org-structure-template (beg end)
  "Automatically quote (with Org syntax) the contents of `denote-region'."
  (when (derived-mode-p 'org-mode)
    (goto-char end)
    (insert "#+end_quote\n")
    (goto-char beg)
    (insert "#+begin_quote\n")))

(add-hook 'denote-region-after-new-note-functions #'my-denote-region-org-structure-template)
#+end_src

With the above in place, calling the ~my-denote-region~ command does
the following:

- It creates a new note as usual, prompting for the relevant data.
- Inserts the contents of the region below the front matter of the new
  note.
- Adds Org-style quotation block markers around the inserted region.
- Adds a link to the URL or file from where ~my-denote-region~ was called.

** Open an existing note or create it if missing
:PROPERTIES:
:CUSTOM_ID: h:ad91ca39-cf10-4e16-b224-fdf78f093883
:END:

#+findex: denote-open-or-create
#+findex: denote-open-or-create-with-command
Sometimes it is necessary to briefly interrupt the ongoing writing
session to open an existing note or, if that is missing, to create it.
This happens when a new tangential thought occurs and the user wants
to confirm that an entry for it is in place.  To this end, Denote
provides the command ~denote-open-or-create~ as well as its more
flexible counterpart ~denote-open-or-create-with-command~.

The ~denote-open-or-create~ prompts to visit a file in the
~denote-directory~.  At this point, the user must type in search terms
that match a file name.  If the input does not return any matches and
the user confirms their choice to proceed (usually by typing RET
twice, depending on the minibuffer settings), ~denote-open-or-create~
will call the ~denote~ command interactively to create a new note.  It
will then use whatever prompts ~denote~ normally has, per the user
option ~denote-prompts~ ([[#h:6a92a8b5-d766-42cc-8e5b-8dc255466a23][Standard note creation]]).  If the title prompt
is involved (the default behaviour), the ~denote-open-or-create~ sets
up this prompt to have the previous input as the default title of the
note to-be-created.  This means that the user can type RET at the
empty prompt to re-use what they typed in previously.  Commands to use
previous inputs from the history are also available (=M-p= or =M-n= in
the minibuffer, which call ~previous-history-element~ and
~next-history-element~ by default).  Accessing the history is helpful
to, for example, make further edits to the available text.

The ~denote-open-or-create-with-command~ is like the above, except
when it is about to create the new note it first prompts for the
specific file-creating command to use ([[#h:17896c8c-d97a-4faa-abf6-31df99746ca6][Points of entry]]).  For example,
the user may want to specify a signature for this new file, so they
can select the ~denote-signature~ command.

Denote provides similar functionality for linking to an existing note
or creating a new one ([[#h:b6056e6b-93df-4e6b-a778-eebd105bac46][Link to a note or create it if missing]]).

** Maintain separate directory silos for notes
:PROPERTIES:
:CUSTOM_ID: h:15719799-a5ff-4e9a-9f10-4ca03ef8f6c5
:END:
#+cindex: Note silos

The user option ~denote-directory~ accepts a value that represents the
path to a directory, such as =~/Documents/notes=. It may also be a
list of related directories ([[#h:e2809afb-5c6c-4a20-9881-00c987bb5345][The ~denote-directory~ option]]). Normally,
the user will have one place where they store all their notes, in
which case this arrangement shall suffice.

There is, however, the possibility to maintain separate and unrelated
directories of notes. By "separate", we mean that they do not
communicate with each other: no linking between them, no common
keywords, nothing. Think of the scenario where one set of notes is for
private use and another is for an employer. We call these separate
directories "silos".

To create silos, the user must specify a local variable at the root of
the desired directory. This is done by creating a =.dir-locals.el=
file, with the following contents:

#+begin_src emacs-lisp
;;; Directory Local Variables.  For more information evaluate:
;;;
;;;     (info "(emacs) Directory Variables")

((nil . ((denote-directory . "/path/to/silo/"))))
#+end_src

When inside the directory that contains this =.dir-locals.el= file,
all Denote commands/functions for note creation, linking, the
inference of available keywords, et cetera will use the silo as their
point of reference ([[#h:e43baf95-f201-4fec-8620-c0eb5eaa1c85][The ~denote-silo~ package which formerly was =denote-silo-extras.el=]]).
They will not read the global value of ~denote-directory~. The global
value of ~denote-directory~ is read everywhere else except the silos.

In concrete terms, this is a representation of the directory structures
(notice the =.dir-locals.el= file is needed only for the silos):

#+begin_example
;; This is the global value of 'denote-directory' (no need for a .dir-locals.el)
~/Documents/notes
|-- 20210303T120534--this-is-a-test__journal_philosophy.txt
|-- 20220303T120534--another-sample__journal_testing.md
`-- 20220620T181255--the-third-test__keyword.org

;; A silo with notes for the employer
~/different/path/to/notes-for-employer
|-- .dir-locals.el
|-- 20210303T120534--this-is-a-test__conference.txt
|-- 20220303T120534--another-sample__meeting.md
`-- 20220620T181255--the-third-test__keyword.org

;; Another silo with notes for my volunteering
~/different/path/to/notes-for-volunteering
|-- .dir-locals.el
|-- 20210303T120534--this-is-a-test__activism.txt
|-- 20220303T120534--another-sample__teambuilding.md
`-- 20220620T181255--the-third-test__keyword.org
#+end_example

It is possible to configure other user options of Denote to have a
silo-specific value.  For example, this one changes the
~denote-known-keywords~ only for this particular silo:

#+begin_src emacs-lisp
;;; Directory Local Variables.  For more information evaluate:
;;;
;;;     (info "(emacs) Directory Variables")

((nil . ((denote-directory . "/path/to/silo/")
         (denote-known-keywords . ("food" "drink")))))
#+end_src

This one is like the above, but also disables ~denote-infer-keywords~:

#+begin_src emacs-lisp
;;; Directory Local Variables.  For more information evaluate:
;;;
;;;     (info "(emacs) Directory Variables")

((nil . ((denote-directory . "/path/to/silo/")
         (denote-known-keywords . ("food" "drink"))
         (denote-infer-keywords . nil))))
#+end_src

To expand the list of local variables to, say, cover specific major
modes, we can do something like this:

#+begin_src emacs-lisp
;;; Directory Local Variables.  For more information evaluate:
;;;
;;;     (info "(emacs) Directory Variables")

((nil . ((denote-directory . "/path/to/silo/")
         (denote-known-keywords . ("food" "drink"))
         (denote-infer-keywords . nil)))
 (org-mode . ((org-hide-emphasis-markers . t)
              (org-hide-macro-markers . t)
              (org-hide-leading-stars . t))))
#+end_src

As not all user options have a "safe" local value, Emacs will ask the
user to confirm their choice and to store it in the Custom code
snippet that is normally appended to init file (or added to the file
specified by the user option ~custom-file~).

Finally, it is possible to have a =.dir-locals.el= for subdirectories
of any ~denote-directory~.  Perhaps to specify a different set of
known keywords, while not making the subdirectory a silo in its own
right.  We shall not expand on such an example, as we trust the user
to experiment with the best setup for their workflow.

Feel welcome to ask for help if the information provided herein is not
sufficient.  The manual shall be expanded accordingly.

*** Make Org export work with silos
:PROPERTIES:
:CUSTOM_ID: h:fed09992-7c43-4237-b48f-f654bc29d1d8
:END:

The Org export infrastructure is designed to ignore directory-local
variables. This means that Denote silos, which depend on setting the
local value of the variable ~denote-directory~, do not work as
intended ([[#h:15719799-a5ff-4e9a-9f10-4ca03ef8f6c5][Maintain separate directory silos for notes]]). More
specifically, the Denote links do not resolve to the right file,
because their path is changed during the export process.

I brought this to the attention of the Org maintainer. The guidance
from their side is to use the =#+bind= keyword to specify a local
value for the ~denote-directory~: <https://lists.gnu.org/archive/html/emacs-orgmode/2024-06/msg00206.html>.
The prerequisite is to set ~org-export-allow-bind-keywords~ to a
non-nil value:

#+begin_src emacs-lisp
(setq org-export-allow-bind-keywords t)
#+end_src

I do not think this is an elegant solution, but here are two possible
ways to go about it, anyway:

1. Manually add the =#+bind= keyword to each file you want to export.
   It has to be like this:

   #+begin_src emacs-lisp
   ,#+bind: denote-directory "/path/to/silo/"
   #+end_src

2. Alternatively, you can make the Org front matter that Denote uses
   for new files automatically include the =#+bind= keyword with its
   desired value. Here is a complete =.dir-locals.el= which (i)
   defines the silo and (ii) modifies the ~denote-org-front-matter~
   accordingly:

   #+begin_src emacs-lisp
   ;;; Directory Local Variables.  For more information evaluate:
   ;;;
   ;;;     (info "(emacs) Directory Variables")

   ((nil . ((denote-directory . "/path/to/silo/")
            (denote-org-front-matter .
             "#+title:      %s
,#+date:       %s
,#+filetags:   %s
,#+identifier: %s
,#+bind:       denote-directory \"/path/to/silo/\"
\n"))))
   #+end_src

   [ Note that if you are reading the Org source of this manual, you
     need to use the command ~org-edit-special~ on the above code
     blocks before copying the code. This is because Org automatically
     prepends a comma to disambiguate those entries from actual
     keywords of the current file. ]

** Exclude certain files from file prompts
:PROPERTIES:
:CUSTOM_ID: h:53db09de-2cec-4670-b163-5cb791f997b4
:END:

#+vindex: denote-excluded-files-regexp
The user option ~denote-excluded-files-regexp~ is a regular expression
that matches files names which should be excluded from all Denote file
prompts. Such prompts are present when linking to a file with one of
the many commands, like ~denote-link~ ([[#h:fc913d54-26c8-4c41-be86-999839e8ad31][Linking notes]]), or when trying
to open a file that may or may not exist ([[#h:ad91ca39-cf10-4e16-b224-fdf78f093883][Open an existing note or create it if missing]]).

Functions that check for files include ~denote-directory-files~ and
~denote-file-prompt~.

The match is performed with ~string-match-p~.

[[#h:c916d8c5-540a-409f-b780-6ccbd90e088e][For developers or advanced users]].

** Exclude certain directories from all operations
:PROPERTIES:
:CUSTOM_ID: h:8458f716-f9c2-4888-824b-2bf01cc5850a
:END:

#+vindex: denote-excluded-directories-regexp
The user option ~denote-excluded-directories-regexp~ instructs all
Denote functions that read or check file/directory names to omit
directories that match the given regular expression.  The regexp needs
to match only the name of the directory, not its full path.

Affected operations include file prompts and functions that return the
available files in the value of the user option ~denote-directory~
([[#h:15719799-a5ff-4e9a-9f10-4ca03ef8f6c5][Maintain separate directory silos for notes]]).

File prompts are used by several commands, such as ~denote-link~ and
~denote-subdirectory~.

Functions that check for files include ~denote-directory-files~ and
~denote-directory-subdirectories~.

The match is performed with ~string-match-p~.

[[#h:c916d8c5-540a-409f-b780-6ccbd90e088e][For developers or advanced users]].

** Exclude certain keywords from being inferred
:PROPERTIES:
:CUSTOM_ID: h:69e518ee-ed43-40ab-a5f4-c780a23e5358
:END:

#+vindex: denote-keywords-to-not-infer-regexp
The user option ~denote-keywords-to-not-infer-regexp~ omits keywords
that match a regular expression from the list of inferred keywords.

[ The ~denote-excluded-keywords-regexp~ is an obsolete alias for
  ~denote-keywords-to-not-infer-regexp~ as part of {{{development-version}}}. ]

Keywords are inferred from file names and provided at relevant prompts
as completion candidates when the user option ~denote-infer-keywords~
is non-nil.

The match is performed with ~string-match-p~.

** Create a controlled vocabulary for keywords
:PROPERTIES:
:CUSTOM_ID: h:c0fb477f-4f99-4d76-9cce-132bcfcb351d
:END:

Denote has two ways to know about keywords: the predefined list of
strings specified in the user option ~denote-known-keywords~ as well
as all the keywords it finds in the files of the ~denote-directory~
when the user option ~denote-infer-keywords~ is set to a non-nil value
([[#h:69e518ee-ed43-40ab-a5f4-c780a23e5358][Exclude certain keywords from being inferred]]).

While this is a viable setup, users may prefer to implement a
"controlled vocabulary". This is a predefined set of keywords whose
purpose is to avoid the creation of overly specific or inconsistent
keywords.

To establish such a controlled vocabulary, users need only have
something like this in their configuration:

#+begin_src emacs-lisp
;; Do not read keywords from files.  The only source is the `denote-known-keywords'.
(setq denote-infer-keywords nil)

;; Define the list of keywords.  Each keyword is a string.
(setq denote-known-keywords (list "politics" "economics" "emacs" "philosophy"))
#+end_src

[ As part of {{{development-version}}}, setting ~denote-infer-keywords~
  to ~nil~ also makes the ~denote-keywords-prompt~ demand that the
  input matches one of the keywords in ~denote-known-keywords~. In
  previous versions, the prompt would accept arbitrary text. ]

** Use Denote commands from the menu bar or context menu
:PROPERTIES:
:CUSTOM_ID: h:c4290e15-e97e-4a9b-b8db-6b9738e37e78
:END:

Denote registers a submenu for the ~menu-bar-mode~.  Users will find
the entry called "Denote".  From there they can use their pointer to
select a command.  For a sample of how this looks, read the
development log: <https://protesilaos.com/codelog/2023-03-31-emacs-denote-menu/>.

#+findex: denote-menu-bar-mode
The command ~denote-menu-bar-mode~ toggles the presentation of the
menu. It is enabled by default.

Emacs also provides support for operations through a context menu.
This is typically the set of actions that are made available via a
right mouse click.  Users who enable ~context-menu-mode~ can register
the Denote entry for it by adding the following to their configuration
file:

#+begin_src emacs-lisp
(add-hook 'context-menu-functions #'denote-context-menu)
#+end_src

* Renaming files
:PROPERTIES:
:CUSTOM_ID: h:532e8e2a-9b7d-41c0-8f4b-3c5cbb7d4dca
:END:

Denote provides commands to rename files and update their front matter
where relevant.  For Denote to work, only the file name needs to be in
order, by following our naming conventions ([[#h:4e9c7512-84dc-4dfb-9fa9-e15d51178e5d][The file-naming scheme]]).
The linking mechanism, in particular, needs just the identifier in the
file name ([[#h:fc913d54-26c8-4c41-be86-999839e8ad31][Linking notes]]).

We write front matter in notes for the user's convenience and for other
tools to make use of that information (e.g. Org's export mechanism).
The renaming mechanism takes care to keep this data in sync with the
file name, when the user performs a change.

Renaming is useful for managing existing files created with Denote,
but also for converting older text files to Denote notes.  Denote's
file-naming scheme is not specific to notes or text files: it is
relevant for all sorts of items, such as multimedia and PDFs that form
part of the user's longer-term storage.  While Denote does not manage
such files (e.g. doesn't create links to them), it already has all the
mechanisms to facilitate the task of renaming them.

#+vindex: denote-after-rename-file-hook
All renaming commands run the ~denote-after-rename-file-hook~ after a
succesful operation ([[#h:a947908e-1847-4471-ba07-377ee2f4b36c][Access the data of the latest note]]). They also
construct the file name in accordance with the user option
~denote-file-name-components-order~ ([[#h:dc8c40e0-233a-4991-9ad3-2cf5f05ef1cd][Change the order of file name components]]).

Apart from renaming files, Denote can also rename only the buffer.
The idea is that the underlying file name is correct but it can be
easier to use shorter buffer names when displaying them on the mode
line or switching between then with commands like ~switch-to-buffer~.

[[#h:3ca4db16-8f26-4d7d-b748-bac48ae32d69][Automatically rename Denote buffers]].

[[#h:9051f15d-ea7e-4b17-adc2-bc6a749c721b][Find duplicate identifiers and put them in a Dired buffer]].

** Rename a single file
:PROPERTIES:
:CUSTOM_ID: h:7cc9e000-806a-48da-945c-711bbc7426b0
:END:

#+findex: denote-rename-file
The ~denote-rename-file~ command renames a file and updates existing
front matter if appropriate. It is possible to do the same with
multiple files ([[#h:1b6b2c78-42f0-45b8-9ef0-6de21a8b2cde][Rename multiple files interactively]]).

It always renames the file where it is located in the file system:
it never moves it to another directory.

If in Dired, it considers =FILE= to be the one at point, else it
prompts with minibuffer completion for one. When called from Lisp,
=FILE= is a file system path represented as a string.

If =FILE= has a Denote-compliant identifier, it retains it while
updating components of the file name referenced by the user option
~denote-prompts~ ([[#h:f9204f1f-fcee-49b1-8081-16a08a338099][The ~denote-prompts~ option]]). By default, these are
the =TITLE= and =KEYWORDS=. The =SIGNATURE= is another one. When
called from Lisp, =TITLE= and =SIGNATURE= are strings, while
=KEYWORDS= is a list of strings.

If there is no identifier, ~denote-rename-file~ creates an identifier
based on the following conditions:

1. If the ~denote-prompts~ includes an entry for date prompts, then it
   prompts for =DATE= and takes its input to produce a new identifier. For
   use in Lisp, =DATE= must conform with ~denote-valid-date-p~.

2. If =DATE= is nil (e.g. when ~denote-prompts~ does not include a
   date entry), it uses the file attributes to determine the last
   modified date of =FILE= and formats it as an identifier.

3. As a fallback, it derives an identifier from the current date and
   time.

4. At any rate, if the resulting identifier is not unique among the
   files in the variable ~denote-directory~, it increments it such
   that it becomes unique.

In interactive use, and assuming ~denote-prompts~ includes a title
entry, the ~denote-rename-file~ makes the =TITLE= prompt have
prefilled text in the minibuffer that consists of the current title of
=FILE=. The current title is either retrieved from the front matter
(such as the =#+title= in Org) or from the file name.

The command does the same for the =SIGNATURE= prompt, subject to
~denote-prompts~, by prefilling the minibuffer with the current
signature of =FILE=, if any.

Same principle for the =KEYWORDS= prompt: it converts the keywords in
the file name into a comma-separated string and prefills the minibuffer
with it (the =KEYWORDS= prompt accepts more than one keywords, each
separated by a comma, else the ~crm-separator~).

For all prompts, the ~denote-rename-file~ interprets an empty input as
an instruction to remove that file name component. For example, if a
=TITLE= prompt is available and =FILE= is =20240211T093531--some-title__keyword1.org=
then it renames =FILE= to =20240211T093531__keyword1.org=.

In interactive use, if there is no entry for a file name component in
~denote-prompts~, keep it as-is ([[#h:f9204f1f-fcee-49b1-8081-16a08a338099][The ~denote-prompts~ option]]).

When called from Lisp, the special symbol `keep-current' can be
used for the TITLE, KEYWORDS, SIGNATURE and DATE parameters to
keep them as-is.

[ NOTE: Please check with your minibuffer user interface how to
  provide an empty input. The Emacs default setup accepts the empty
  minibuffer contents as they are, though popular packages like
  ~vertico~ use the first available completion candidate instead. For
  ~vertico~, the user must either move one up to select the prompt and
  then type =RET= there with empty contents, or use the command
  ~vertico-exit-input~ with empty contents. That Vertico command is
  bound to =M-RET= as of this writing on 2024-02-13 08:08 +0200. ]

When renaming =FILE=, the command reads its file type extension (like
=.org=) and preserves it through the renaming process. Files that have
no extension are left without one.

As a final step, ask for confirmation, showing the difference
between old and new file names.  Do not ask for confirmation if
the user option ~denote-rename-confirmations~ does not contain
the symbol ~modify-file-name~ ([[#h:a2ae9090-c49e-4b32-bcf5-eb8944241fd7][The ~denote-rename-confirmations~ option]]).

If =FILE= has front matter for =TITLE= and =KEYWORDS=, ask to rewrite
their values in order to reflect the new input, unless
~denote-rename-confirmations~ lacks ~rewrite-front-matter~. When the
~denote-save-buffers~ is nil (the default), do not save the underlying
buffer, thus giving the user the option to double-check the result,
such as by invoking the command ~diff-buffer-with-file~. The rewrite
of the =TITLE= and =KEYWORDS= in the front matter should not affect
the rest of the front matter.

If the file does not have front matter but is among the supported file
types (per ~denote-file-type~), add front matter to the top of it and
leave the buffer unsaved for further inspection ([[#h:13218826-56a5-482a-9b91-5b6de4f14261][Front matter]]). Save
the buffer if ~denote-save-buffers~ is non-nil ([[#h:bf80f4cd-6f56-4f7c-a991-8573161e4511][The ~denote-save-buffers~ option]]).

Construct the file name in accordance with the user option
~denote-file-name-components-order~ ([[#h:dc8c40e0-233a-4991-9ad3-2cf5f05ef1cd][Change the order of file name components]]).

Run the ~denote-after-rename-file-hook~ after renaming =FILE= ([[#h:a947908e-1847-4471-ba07-377ee2f4b36c][Access the data of the latest note]]).

This command is intended to (i) rename Denote files, (ii) convert
existing supported file types to Denote notes, and (ii) rename
non-note files (e.g. =PDF=) that can benefit from Denote's file-naming
scheme.

For a version of this command that works with multiple files
one-by-one, use ~denote-dired-rename-files~ ([[#h:1b6b2c78-42f0-45b8-9ef0-6de21a8b2cde][Rename multiple files interactively]]).

*** The ~denote-rename-confirmations~ option
:PROPERTIES:
:CUSTOM_ID: h:a2ae9090-c49e-4b32-bcf5-eb8944241fd7
:END:

#+vindex: denote-rename-confirmations
The user option ~denote-rename-confirmations~ controls what kind of
confirmation renaming commands ask for ([[#h:532e8e2a-9b7d-41c0-8f4b-3c5cbb7d4dca][Renaming files]]).  Its value is
a list of symbols.

The value is either nil, in which case no confirmation is ever
requested, or a list of symbols among the following:

- ~modify-file-name~ means that renaming commands will ask for
  confirmation before modifying the file name.

- ~rewrite-front-matter~ means that renaming commands will ask for
  confirmation before rewritting the front matter.

- ~add-front-matter~ means that renaming commands will ask for
  confirmation before adding new front matter to the file.

The default behaviour of the ~denote-rename-file~ command (and others
like it) is to ask for an affirmative answer as a final step before
changing the file name and, where relevant, inserting or updating the
corresponding front matter.

Specialized commands that build on top of ~denote-rename-file~ (or
related) may internally bind this user option to a non-nil value in
order to perform their operation (e.g. ~denote-dired-rename-files~
goes through each marked Dired file, prompting for the information to
use, but carries out the renaming without asking for confirmation
([[#h:1b6b2c78-42f0-45b8-9ef0-6de21a8b2cde][Rename multiple files interactively]])).

** Rename a single file based on its front matter
:PROPERTIES:
:CUSTOM_ID: h:3ab08ff4-81fa-4d24-99cb-79f97c13a373
:END:

#+findex: denote-rename-file-using-front-matter
In the previous section, we covered the more general mechanism of the
command ~denote-rename-file~ ([[#h:7cc9e000-806a-48da-945c-711bbc7426b0][Rename a single file]]).  There is also a
way to have the same outcome by making Denote read the data in the
current file's front matter and use it to construct/update the file
name.  The command for this is ~denote-rename-file-using-front-matter~.
It is only relevant for files that (i) are among the supported file
types, per ~denote-file-type~, and (ii) have the requisite front matter
in place.

Suppose you have an =.org= file with this front matter ([[#h:13218826-56a5-482a-9b91-5b6de4f14261][Front matter]]):

#+begin_example
#+title:      My sample note file
#+date:       [2022-08-05 Fri 13:10]
#+filetags:   :testing:
#+identifier: 20220805T131044
#+end_example

Its file name reflects this information:

: 20220805T131044--my-sample-note-file__testing.org

You want to change its title and keywords manually, so you modify it thus:

#+begin_example
#+title:      My modified sample note file
#+date:       [2022-08-05 Fri 13:10]
#+filetags:   :testing:denote:emacs:
#+identifier: 20220805T131044
#+end_example

At this stage, the file name still shows the old title and keywords.
You now invoke ~denote-rename-file-using-front-matter~ and it updates
the file name to:

: 20220805T131044--my-modified-sample-note-file__testing_denote_emacs.org

By default, the renaming is subject to a "yes or no" prompt that shows
the old and new names, just so the user is certain about the change.
Though this can be modified ([[#h:a2ae9090-c49e-4b32-bcf5-eb8944241fd7][The ~denote-rename-confirmations~ option]]).

The identifier of the file, if any, is never modified even if it is
edited in the front matter: Denote considers the file name to be the
source of truth in this case, to avoid potential breakage with typos and
the like.

This command constructs the file name in accordance with the user option
~denote-file-name-components-order~ ([[#h:dc8c40e0-233a-4991-9ad3-2cf5f05ef1cd][Change the order of file name components]]).

** Rename multiple files interactively
:PROPERTIES:
:CUSTOM_ID: h:1b6b2c78-42f0-45b8-9ef0-6de21a8b2cde
:END:

#+findex: denote-dired-rename-files
#+findex: denote-dired-rename-marked-files
The command ~denote-dired-rename-files~ (alias ~denote-dired-rename-marked-files~)
renames the files that are marked in a Dired buffer. Its behaviour is
similar to the ~denote-rename-file~ in that it prompts for a title,
keywords, and signature ([[#h:7cc9e000-806a-48da-945c-711bbc7426b0][Rename a single file]]). It does so over each
marked file, renaming one after the other.

Unlike ~denote-rename-file~, the command ~denote-dired-rename-files~
does not ask to confirm the changes made to the files: it performs
them outright (same as setting ~denote-rename-confirmations~ to a nil
value). This is done to make it easier to rename multiple files
without having to confirm each step. For an even more direct approach,
check the command ~denote-dired-rename-marked-files-with-keywords~.

- [[#h:f365ff7e-2140-4e14-a92f-666ae97382a4][Rename by writing only keywords]]
- [[#h:ea5673cd-e6ca-4c42-a066-07dc6c9d57f8][Rename multiple files based on their front matter]]

** Rename multiple files at once by asking only for keywords
:PROPERTIES:
:CUSTOM_ID: h:f365ff7e-2140-4e14-a92f-666ae97382a4
:END:

#+findex: denote-dired-rename-marked-files-with-keywords
The ~denote-dired-rename-marked-files-with-keywords~ command renames
marked files in Dired to conform with our file-naming scheme. It does
so by writing keywords to them. Specifically, it does the following:

- retains the file's existing name and makes it the =TITLE= field, per
  Denote's file-naming scheme;

- sluggifies the =TITLE= and adjusts its letter casing, according to
  our conventions;

- prepends an identifier to the =TITLE=, if one is missing;

- preserves the file's extension, if any;

- prompts once for =KEYWORDS= and applies the user's input to the
  corresponding field in the file name, rewriting any keywords that
  may exist while removing keywords that do exist if =KEYWORDS= is
  empty;

- adds or rewrites existing front matter to the underlying file, if it
  is recognized as a Denote note (per the ~denote-file-type~ user
  option), such that it includes the new keywords.

[ Note that the affected buffers are not saved, unless the user option
  ~denote-rename-no-confirm~ is non-nil. Users can thus check them to
  confirm that the new front matter does not cause any problems (e.g.
  with the ~diff-buffer-with-file~ command). Multiple buffers can be
  saved in one go with the command ~save-some-buffers~ (read its doc
  string). ]

Construct the file name in accordance with the user option
~denote-file-name-components-order~ ([[#h:dc8c40e0-233a-4991-9ad3-2cf5f05ef1cd][Change the order of file name components]]).

Run the ~denote-after-rename-file-hook~ after the renaming is done.

#+findex: denote-dired-rename-marked-files-add-keywords
#+findex: denote-dired-rename-marked-files-remove-keywords
For more specialized versions of this command that only add or remove
keywords, use ~denote-dired-rename-marked-files-add-keywords~ and
~denote-dired-rename-marked-files-remove-keywords~, respectively.

** Rename multiple files based on their front matter
:PROPERTIES:
:CUSTOM_ID: h:ea5673cd-e6ca-4c42-a066-07dc6c9d57f8
:END:

#+findex: denote-dired-rename-marked-files-using-front-matter
As already noted, Denote can rename a file based on the data in its
front matter ([[#h:3ab08ff4-81fa-4d24-99cb-79f97c13a373][Rename a single file based on its front matter]]).  The
command ~denote-dired-rename-marked-files-using-front-matter~ extends
this principle to a batch operation which applies to all marked files in
Dired.

Marked files must count as notes for the purposes of Denote, which
means that they at least have an identifier in their file name and use
a supported file type, per ~denote-file-type~. Files that do not meet
this criterion are ignored, because Denote cannot know if they have
front matter and what that may be. For such files, it is still
possible to rename them interactively ([[#h:1b6b2c78-42f0-45b8-9ef0-6de21a8b2cde][Rename multiple files interactively]]).

** Rename a file by changing only its file type
:PROPERTIES:
:CUSTOM_ID: h:85b65995-89fd-4978-bba3-7bb6c8d6f945
:END:

#+findex: denote-change-file-type-and-front-matter
The command ~denote-change-file-type-and-front-matter~ provides the
convenience of converting a note taken in one file type, say, =.txt=
into another like =.org=. It presents a choice among the
~denote-file-type~ options.

The conversion does NOT modify the existing front matter.  Instead, it
prepends new front matter to the top of the file.  We do this as a
safety precaution since the user can, in principle, add arbitrary
extras to their front matter that we would not want to touch.

If in Dired, ~denote-change-file-type-and-front-matter~ operates on the
file at point, else the current file, else it prompts with minibuffer
completion for one.

The title of the file is retrieved from a line starting with a title
field in the file's front matter, depending on the previous file type
(e.g.  =#+title= for Org).  The same process applies for keywords.

As a final step, the command asks for confirmation, showing the
difference between old and new file names.

This command constructs the file name in accordance with the user option
~denote-file-name-components-order~ ([[#h:dc8c40e0-233a-4991-9ad3-2cf5f05ef1cd][Change the order of file name components]]).

** Rename a file by adding or removing a title interactively
:PROPERTIES:
:CUSTOM_ID: h:a26e28c7-8222-4377-92e9-3b0a709010a5
:END:

#+findex: denote-rename-file-title
The command ~denote-rename-file-title~ streamlines the process of
interactively adding or removing a title to/from a file, while
changing its file name accordingly. It asks for a title using the
familiar minibuffer prompt ([[#h:6a92a8b5-d766-42cc-8e5b-8dc255466a23][Standard note creation]]). It then renames
the file. The command respect the values of
~denote-rename-confirmations~ and ~denote-save-buffers~:

- [[#h:a2ae9090-c49e-4b32-bcf5-eb8944241fd7][The ~denote-rename-confirmations~ option]].
- [[#h:bf80f4cd-6f56-4f7c-a991-8573161e4511][The ~denote-save-buffers~ option]].

Technically, ~denote-rename-file-title~ is a wrapper for
~denote-rename-file~, doing all the things that does ([[#h:7cc9e000-806a-48da-945c-711bbc7426b0][Rename a single file]]).

Concretely, this command can add or remove a title in one go. It
does it by prepopulating the minibuffer prompt with the existing
title. Users can then modify it. An empty input means to remove
the title altogether ([[#h:4e9c7512-84dc-4dfb-9fa9-e15d51178e5d][The file-naming scheme]]).

[ NOTE: Please check with your minibuffer user interface how to
  provide an empty input. The Emacs default setup accepts the empty
  minibuffer contents as they are, though popular packages like
  ~vertico~ use the first available completion candidate instead. For
  ~vertico~, the user must either move one up to select the prompt and
  then type =RET= there with empty contents, or use the command
  ~vertico-exit-input~ with empty contents. That Vertico command is
  bound to =M-RET= as of this writing on 2024-06-30 10:37 +0300. ]

** Rename a file by adding or removing keywords interactively
:PROPERTIES:
:CUSTOM_ID: h:ad4dde4a-8e88-470a-97ae-e7b9d4b41fb4
:END:

#+findex: denote-rename-file-keywords
The command ~denote-rename-file-keywords~ streamlines the process of
interactively adding or removing keywords to a file, while changing
its file name and front matter accordingly. It asks for keywords using
the familiar minibuffer prompt ([[#h:6a92a8b5-d766-42cc-8e5b-8dc255466a23][Standard note creation]]). It then
renames the file ([[#h:3ab08ff4-81fa-4d24-99cb-79f97c13a373][Rename a single file based on its front matter]]).
The command respect the values of ~denote-rename-confirmations~ and
~denote-save-buffers~:

- [[#h:a2ae9090-c49e-4b32-bcf5-eb8944241fd7][The ~denote-rename-confirmations~ option]].
- [[#h:bf80f4cd-6f56-4f7c-a991-8573161e4511][The ~denote-save-buffers~ option]].

Technically, ~denote-rename-file-keywords~ is a wrapper for
~denote-rename-file~, doing all the things that does ([[#h:7cc9e000-806a-48da-945c-711bbc7426b0][Rename a single file]]).

Concretely, this command can add or remove keywords in one go. It does
it by prepopulating the minibuffer prompt with the existing keywords.
Users can then use the ~crm-separator~ (normally a comma), to write
new keywords or edit what is in the prompt to rewrite them
accordingly. An empty input means to remove all keywords ([[#h:4e9c7512-84dc-4dfb-9fa9-e15d51178e5d][The file-naming scheme]]).

[ NOTE: Please check with your minibuffer user interface how to
  provide an empty input. The Emacs default setup accepts the empty
  minibuffer contents as they are, though popular packages like
  ~vertico~ use the first available completion candidate instead. For
  ~vertico~, the user must either move one up to select the prompt and
  then type =RET= there with empty contents, or use the command
  ~vertico-exit-input~ with empty contents. That Vertico command is
  bound to =M-RET= as of this writing on 2024-06-30 10:37 +0300. ]

** Rename a file by adding or removing a signature interactively
:PROPERTIES:
:CUSTOM_ID: h:b08a350f-b269-47ed-8c2a-b8ecf1b63c7f
:END:

#+findex: denote-rename-file-signature
The command ~denote-rename-file-signature~ streamlines the process of
interactively adding or removing a signature to/from a file, while
changing its file name accordingly. It asks for a signature using the
familiar minibuffer prompt ([[#h:6a92a8b5-d766-42cc-8e5b-8dc255466a23][Standard note creation]]). It then renames
the file. The command respect the values of
~denote-rename-confirmations~ and ~denote-save-buffers~:

- [[#h:a2ae9090-c49e-4b32-bcf5-eb8944241fd7][The ~denote-rename-confirmations~ option]].
- [[#h:bf80f4cd-6f56-4f7c-a991-8573161e4511][The ~denote-save-buffers~ option]].

Technically, ~denote-rename-file-signature~ is a wrapper for
~denote-rename-file~, doing all the things that does ([[#h:7cc9e000-806a-48da-945c-711bbc7426b0][Rename a single file]]).

Concretely, this command can add or remove a signature in one go. It
does it by prepopulating the minibuffer prompt with the existing
signature. Users can then modify it. An empty input means to remove
the signature altogether ([[#h:4e9c7512-84dc-4dfb-9fa9-e15d51178e5d][The file-naming scheme]]).

[ NOTE: Please check with your minibuffer user interface how to
  provide an empty input. The Emacs default setup accepts the empty
  minibuffer contents as they are, though popular packages like
  ~vertico~ use the first available completion candidate instead. For
  ~vertico~, the user must either move one up to select the prompt and
  then type =RET= there with empty contents, or use the command
  ~vertico-exit-input~ with empty contents. That Vertico command is
  bound to =M-RET= as of this writing on 2024-06-30 10:37 +0300. ]

** Find duplicate identifiers and put them in a Dired buffer
:PROPERTIES:
:CUSTOM_ID: h:9051f15d-ea7e-4b17-adc2-bc6a749c721b
:END:

Denote takes care to create unique identifiers, though its mechanism
relies on reading the existing identifiers in the ~denote-directory~
or the current directory. When we are renaming files across different
directories, there is a small chance that some files have the same
attributes and are thus assigned identical identifiers. If those files
ever make it into a consolidated ~denote-directory~, we will have
duplicates, which break the linking mechanism.

As this is an edge case, we do not include any code to address it in
the Denote code base. Though here is a way to find duplicate
identifiers inside the current directory:

#+begin_src emacs-lisp
(defun my-denote--get-files-in-dir (directory)
  "Return file names in DIRECTORY."
  (directory-files directory :full-paths directory-files-no-dot-files-regexp))

(defun my-denote--same-identifier-p (file1 file2)
  "Return non-nil if FILE1 and FILE2 have the same identifier."
  (let ((id1 (denote-retrieve-filename-identifier file1))
        (id2 (denote-retrieve-filename-identifier file2)))
    (equal id1 id2)))

(defun my-denote-find-duplicate-identifiers (directory)
  "Find all files in DIRECTORY that need a new identifier."
  (let* ((ids (my-denote--get-files-in-dir directory))
         (unique-ids (seq-uniq ids #'my-denote--same-identifier-p)))
    (seq-difference ids unique-ids #'equal)))

(defun my-denote-dired-show-duplicate-identifiers (directory)
  "Put duplicate identifiers from DIRECTORY in a dedicated Dired buffer."
  (interactive
   (list
    (read-directory-name "Select DIRECTORY to check for duplicate identifiers: " default-directory)))
  (if-let* ((duplicates (my-denote-find-duplicate-identifiers directory)))
      (dired (cons (format "Denote duplicate identifiers" directory) duplicates))
    (message "No duplicates identifiers in `%s'" directory)))
#+end_src

Evaluate this code and then call the command ~my-denote-dired-show-duplicate-identifiers~.
If there are duplicates, it will put them in a dedicated Dired buffer.
From there, you can view the file contents as usual, and manually edit
the identifiers as you see fit (e.g. edit them one by one, or change
to the writable Dired and record a keyboard macro that makes use of a
counter to increment by 1---contact me if you need any help).

** Faces used by rename commands
:PROPERTIES:
:CUSTOM_ID: h:ab3f355a-f763-43ae-a4c9-179d2d9265a5
:END:

These are the faces used by the various Denote rename commands to
style or highlight the old/new/current file shown in the relevant
minibuffer prompts:

- ~denote-faces-prompt-current-name~
- ~denote-faces-prompt-new-name~
- ~denote-faces-prompt-old-name~

* The file-naming scheme
:PROPERTIES:
:CUSTOM_ID: h:4e9c7512-84dc-4dfb-9fa9-e15d51178e5d
:END:

#+vindex: denote-directory
Notes are stored in the ~denote-directory~.  The default path is
=~/Documents/notes=.  The ~denote-directory~ can be a flat listing,
meaning that it has no subdirectories, or it can be a directory tree.
Either way, Denote takes care to only consider "notes" as valid
candidates in the relevant operations and will omit other files or
directories.

Every note produced by Denote follows this pattern by default
([[#h:17896c8c-d97a-4faa-abf6-31df99746ca6][Points of entry]]):

: @@ID==SIGNATURE--TITLE__KEYWORDS.EXTENSION

The =ID= field represents the identifier which, by default, is the
date in year-month-day format followed by the capital letter =T= (for
"time") and the current time in hour-minute-second notation. The
presentation is compact: =20220531T091625=. When it has this format
(the default), the delimiter (=@@=) is optional. The =ID= serves as
the unique identifier of each note and, as such, is also known as the
file's ID or identifier. The =ID= can be any string: it does not need
to be associated with a date ([[#h:3048f558-7d84-45d6-9ef2-53055483e801][Define a completely custom identifier scheme]]).

File names can include an arbitrary string of alphanumeric characters
in the =SIGNATURE= field. Signatures have no clearly defined purpose
and are up to the user to define. They can serve as special labels,
such as =part1= and =part2= of a large file, or as priority indicators
like =a=, =b=, =c=, or even context/scope specifiers like =home= and
=work=. Another use-case is to write sequences of thoughts, such that
notes form a hierarchy, something we support with the optional and
comprehensive extension =denote-sequence.el= ([[#h:d5ca722d-e7fa-46fa-9a57-6363b1d4186f][Write sequence notes or "folgezettel"]]).
Signatures are an optional extension to Denote's file-naming scheme.
In the simplest form, they can be added to newly created files on
demand, with the command ~denote-signature~, or by modifying the value
of the user option ~denote-prompts~ ([[#h:f9204f1f-fcee-49b1-8081-16a08a338099][The ~denote-prompts~ option]]).

The =TITLE= field is the title of the note, as provided by the user.
It can contain any character, though the default is to have it
downcased and hyphenated ([[#h:ae8b19a1-7f67-4258-96b3-370a72c43f4e][Sluggification of file name components]]). An
entry about "Economics in the Euro Area" produces an
=economics-in-the-euro-area= string for the =TITLE= of the file name.

The =KEYWORDS= field consists of one or more entries demarcated by an
underscore (the separator is inserted automatically).  Each keyword is
a string provided by the user at the relevant prompt which broadly
describes the contents of the entry.

Each of the keywords is a single word, with multiple keywords providing
the multi-dimensionality needed for advanced searches through Denote
files.  Users who need to compose a keyword out of multiple words such
as camelCase/CamelCase and are encouraged to use the
~denote-file-name-slug-functions~ user option accordingly
([[#h:ae8b19a1-7f67-4258-96b3-370a72c43f4e][Sluggification of file name components]]).

#+vindex: denote-file-type
The =EXTENSION= is the file type.  By default, it is =.org= (~org-mode~)
though the user option ~denote-file-type~ provides support for Markdown
with YAML or TOML variants (=.md= which runs ~markdown-mode~) and plain
text (=.txt= via ~text-mode~).  Consult its doc string for the minutiae.
While files end in the =.org= extension by default, the Denote code base
does not actually depend on org.el and/or its accoutrements.

Examples:

: 20220610T043241--initial-thoughts-on-the-zettelkasten-method__notetaking.org
: 20220610T062201--define-custom-org-hyperlink-type__denote_emacs_package.md
: 20220610T162327--on-hierarchy-and-taxis__notetaking_philosophy.txt

The different field separators, namely =--= and =__= introduce an
efficient way to anchor searches (such as with Emacs commands like
~isearch~ or from the command-line with ~find~ and related).  A query
for =_word= always matches a keyword, while a regexp in the form of,
say, ="\\([0-9T]+?\\)--\\(.*?\\)_"= captures the date in group =\1= and
the title in =\2= (test any regular expression in the current buffer by
invoking =M-x re-builder=).

[[#h:1a953736-86c2-420b-b566-fb22c97df197][Features of the file-naming scheme for searching or filtering]].

All file name fields can contain any character, are optional and can
appear in any order. The following permutations are valid:

: ID.EXT
: ID--TITLE.EXT
: ID__KEYWORDS.EXT
: ID==SIGNATURE.EXT
: ID==SIGNATURE--TITLE.EXT
: ID==SIGNATURE--TITLE__KEYWORDS.EXT
: ID==SIGNATURE__KEYWORDS.EXT

Commands such as ~denote~ or ~denote-rename-file~ will prompt for the
file name fields configured in ~denote-prompts~.

When in doubt, stick to the default design, which is carefully
considered and works well ([[#h:dc8c40e0-233a-4991-9ad3-2cf5f05ef1cd][Change the order of file name components]]).

While Denote is an Emacs package, notes should work long-term and not
depend on the functionality of a specific program.  The file-naming
scheme we apply guarantees that a listing is readable in a variety of
contexts.  The Denote file-naming scheme is, in essence, an effective,
low-tech invention.

** Change the order of file name components
:PROPERTIES:
:CUSTOM_ID: h:dc8c40e0-233a-4991-9ad3-2cf5f05ef1cd
:END:

#+vindex: denote-file-name-components-order
Our standard file-naming scheme prescribes a specific order for the
file name components ([[#h:4e9c7512-84dc-4dfb-9fa9-e15d51178e5d][The file-naming scheme]]). Though we provide the
user option ~denote-file-name-components-order~ to let the user
reorder them as they see fit.

The value of this user option is a list of the following symbols:

- ~identifier~: By default, this is the combination of the date and
  time. When it is the first on the list, it looks like
  =20240519T073456= and does not have a component separator of its own
  due to its unambiguous format. When it is placed anywhere else in
  the file name, it is prefixed with =@@=, so it looks like
  =@@20240519T073456=.

- ~signature~: This is an arbitrary string that can be used to qualify
  the file in some way, according to the user's methodology (e.g. to
  add a sequence to notes). The string is always prefixed with the
  ~==~ to remain unambiguous.

- ~title~: This is an arbitrary string which describes the file. It is
  always prefixed with =--= to be unambiguous.

- ~keywords~: This is a series of one or more words that succinctly
  group the file. Multiple keywords are separated by an underscore
  prefixed to each of them. The file name component is always prefixed
  with =__=.

All four symbols must appear exactly once. Duplicates are ignored. Any
missing symbol is added automatically. Note that even though all four
symbols must appear in the user option
~denote-file-name-components-order~, actual files may not contain a
specific component. For instance, a note without keywords or signature
is valid.

Some examples:

#+begin_src emacs-lisp
(setq denote-file-name-components-order '(identifier signature title keywords))
;; => 20240519T07345==hello--this-is-the-title__denote_testing.org

(setq denote-file-name-components-order '(signature identifier title keywords))
;; => ==hello@@20240519T07345--this-is-the-title__denote_testing.org

(setq denote-file-name-components-order '(title signature identifier keywords))
;; => --this-is-the-title==hello@@20240519T07345__denote_testing.org

(setq denote-file-name-components-order '(keywords title signature identifier))
;; => __denote_testing--this-is-the-title==hello@@20240519T07345.org
#+end_src

Also see how to configure the Denote prompts, which affect which
components are actually prompted for in creation or renaming commands
([[#h:f9204f1f-fcee-49b1-8081-16a08a338099][The ~denote-prompts~ option]]).

Before deciding on this, please consider the longer-term implications
of file names with varying patterns. Consistency makes things
predictable and thus easier to find. So pick one order and never touch
it again. When in doubt, leave the default file-naming scheme as-is.

*** Retroactively reorder the components of Denote file names
:PROPERTIES:
:CUSTOM_ID: h:c10d2b5f-edb7-4bdf-bc0d-a7c7c91064bf
:END:

While experimenting with the ~denote-file-name-components-order~ to
change the way Denote formats file names, you may end up with files
that look inconsistent. They still work the same way as before, but
you prefer to enforce the same order across your Denote files. The
following custom command does just that. It technically "renames" the
files it is applied to, though only insofar as reordering their Denote
file name components, but not changing the contents of those
components.

#+begin_src emacs-lisp
(defun my-denote-rename-all-to-reorder-components ()
  "Call `denote-dired-rename-files' without any prompts.
In other words, preserve the value of each Denote file name component.

Use this command if you want to modify the user option
`denote-file-name-components-order' and then want your files to
retroactively follow that order."
  (interactive)
  (let ((denote-prompts nil))
    (call-interactively 'denote-dired-rename-files)))
#+end_src

Simply go to a Dired buffer, mark the files you wish to operate on,
and call the command. You may also use the ~denote-dired~ command to
produce a filtered+sorted flat listing of your Denote files, mark
them, and then invoke ~my-denote-rename-all-to-reorder-components~
([[#h:9fe01e63-f34f-4479-8713-f162a5ca865e][Display filtered and sorted files with ~denote-sort-dired~ or ~denote-dired~]]).

Video demonstration: <https://protesilaos.com/codelog/2025-07-09-emacs-denote-reorder-components/>.

DEVELOPMENT NOTE: If you have a more specific use-case, then we can
discuss it and expand the documentation we provide herein.

** Sluggification of file name components
:PROPERTIES:
:CUSTOM_ID: h:ae8b19a1-7f67-4258-96b3-370a72c43f4e
:END:

File names can contain any character that the file system permits.
Denote imposes a few additional restrictions:

+ The tokens "==", =__= and =--= are interpreted by Denote and should
  appear only once.

+ The dot character is not allowed in a note's file name, except to
  indicate the file type extension. Denote recognises two extensions
  for encrypted files, like =.txt.gpg=.

By default, Denote enforces other rules to file names through the user
option ~denote-file-name-slug-functions~. These rules are applied to
file names by default:

+ Many "special characters" are removed.

+ Input for a file title is hyphenated.  The original value is
  preserved in the note's content ([[#h:13218826-56a5-482a-9b91-5b6de4f14261][Front matter]]).

+ Spaces or other delimiters are removed from keywords, meaning that
  =hello-world= becomes =helloworld=.  This is because hyphens in
  keywords do not work everywhere, such as in Org. Plus, hyphens are
  word separators in the title and we want to keep distinct separators
  for each component to make search easier and semantic
  ([[#h:1a953736-86c2-420b-b566-fb22c97df197][Features of the file-naming scheme for searching or filtering]]).

+ Signatures are like the above, but use the equals sign instead of
  hyphens as a word separator.

+ All file name components are downcased. Further down we document how
  to deviate from these rules, such as to accept input of the form
  =helloWorld= or =HelloWorld= verbatim.

Denote imposes these restrictions to enforce uniformity, which is
helpful long-term as it keeps all files with the same predictable
pattern. Too many permutations make searches more difficult to express
accurately and be confident that the matches cover all files.
Nevertheless, one of the principles of Denote is its flexibility or
hackability and so users can deviate from the aforementioned
([[#h:d375c6d2-92c7-425f-9d9d-219ff47ed2a3][User-defined sluggification of file name components]]).

** User-defined sluggification of file name components
:PROPERTIES:
:CUSTOM_ID: h:d375c6d2-92c7-425f-9d9d-219ff47ed2a3
:END:

#+vindex: denote-file-name-slug-functions
The user option ~denote-file-name-slug-functions~ controls the
sluggification of file name components ([[#h:ae8b19a1-7f67-4258-96b3-370a72c43f4e][Sluggification of file name components]]).
The default method is outlined above and in the previous section
([[#h:4e9c7512-84dc-4dfb-9fa9-e15d51178e5d][The file-naming scheme]]).

The value of this user option is an alist where each element is a cons
cell of the form =(COMPONENT . METHOD)=. For example, here is the
default value:

#+begin_example emacs-lisp
'((title . denote-sluggify-title)
  (signature . denote-sluggify-signature)
  (keyword . denote-sluggify-keyword))
#+end_example

- The =COMPONENT= is an unquoted symbol among =title=, =signature=,
  =keyword=, which refers to the corresponding component of the file
  name.

- The =METHOD= is a function to format the given component. This
  function must take a string as its parameter and return the string
  formatted for the file name. Note that even in the case of the
  =keyword= component, the function receives one string representing a
  single keyword and returns it formatted for the file name. Joining
  the keywords together is handled internally by Denote.

One commonly requested deviation from the sluggification rules is to
not sluggify individual keywords, such that the user's input is taken
as-is. This can be done as follows:

#+begin_src emacs-lisp
(setq denote-file-name-slug-functions
      '((title . denote-sluggify-title)
        (keyword . identity)
        (signature . denote-sluggify-signature)))
#+end_src

The ~identity~ function simply returns the string it receives, thus
not altering it in any way.

Another approach is to keep the sluggification but not downcase the
string. We can do this by modifying the original functions used by
Denote. For example, we have this:

#+begin_src emacs-lisp
;; The original function for reference
(defun denote-sluggify-title (str)
  "Make STR an appropriate slug for title."
  (downcase
   (denote-slug-hyphenate
    (replace-regexp-in-string "[][{}!@#$%^&*()+'\"?,.\|;:~`‘’“”/=]*" "" str))))

;; Our variant of the above, which does the same thing except from
;; downcasing the string.
(defun my-denote-sluggify-title (str)
  "Make STR an appropriate slug for title."
  (denote-slug-hyphenate
   (replace-regexp-in-string "[][{}!@#$%^&*()+'\"?,.\|;:~`‘’“”/=]*" "" str)))

;; Now we use our function to sluggify titles without affecting their
;; letter casing.
(setq denote-file-name-slug-functions
      '((title . my-denote-sluggify-title) ; our function here
        (signature . denote-sluggify-signature)
        (keyword . denote-sluggify-keyword)))
#+end_src

Follow this principle for all the sluggification functions ([[#h:d1e4eb5b-e7f2-4a3b-9243-e1c653817a4a][Custom sluggification to remove non-ASCII characters]]).

To access the source code, use either of the following built-in
methods:

1. Call the command ~find-library~ and search for ~denote~. Then
   navigate to the symbol you are searching for.

2. Invoke the command ~describe-symbol~, search for the symbol you are
   interested in, and from the resulting Help buffer either click on
   the first link or do =M-x help-view-source= (bound to =s= in Help
   buffers, by default).

Remember that deviating from the default file-naming scheme of Denote
will make things harder to use in the future, as files can/will have
permutations that create uncertainty. The sluggification scheme and
concomitant restrictions we impose by default are there for a very
good reason: they are the distillation of years of experience. Here we
give you what you wish, but bear in mind it may not be what you need.
You have been warned.

*** Custom sluggification to remove non-ASCII characters
:PROPERTIES:
:CUSTOM_ID: h:d1e4eb5b-e7f2-4a3b-9243-e1c653817a4a
:END:

A common use-case for Denote is to rename files such as videos
downloaded from the Internet. Sometimes, those files have Unicode
characters that (i) not all fonts support and (ii) create all sorts of
problems with pattern matching, such as when searching through file
names.

By default, Denote does not remove Unicode characters because users
may actually want them (e.g. Latin characters with accents). Those who
do, however, wish to keep everything limited to the ASCII range can
use the following in their Emacs configuration ([[#h:d375c6d2-92c7-425f-9d9d-219ff47ed2a3][User-defined sluggification of file name components]]).

#+begin_src emacs-lisp
;; These are the same as the default Denote sluggification functions,
;; except they remove all non-ASCII characters.
(defun my-denote-sluggify-title (str)
  (downcase
   (denote-slug-hyphenate
    (replace-regexp-in-string "[][{}!@#$%^&*()+'\"?,.\|;:~`‘’“”/=]*" ""
                              (denote-slug-keep-only-ascii str)))))

(defun my-denote-sluggify-signature (str)
  (downcase
   (denote-slug-put-equals
    (replace-regexp-in-string "[][{}!@#$%^&*()+'\"?,.\|;:~`‘’“”/-]*" ""
                              (denote-slug-keep-only-ascii str)))))

(defun my-denote-sluggify-keyword (str)
  (downcase
   (replace-regexp-in-string "[][{}!@#$%^&*()+'\"?,.\|;:~`‘’“”/_ =-]*" ""
                             (denote-slug-keep-only-ascii str))))

(defcustom denote-file-name-slug-functions
  '((title . my-denote-sluggify-title)
    (signature . my-denote-sluggify-signature)
    (keyword . my-denote-sluggify-keyword)))
#+end_src

** Features of the file-naming scheme for searching or filtering
:PROPERTIES:
:CUSTOM_ID: h:1a953736-86c2-420b-b566-fb22c97df197
:END:

By default, file names have three fields and two sets of field
delimiters between them:

: ID--TITLE__KEYWORDS.EXTENSION

When a signature is present, this becomes:

: ID==SIGNATURE--TITLE__KEYWORDS.EXTENSION

Field delimiters practically serve as anchors for easier searching.
Consider this example:

: 20220621T062327==1a2--introduction-to-denote__denote_emacs.txt

You will notice that there are two matches for the word =denote=: one
in the title field and another in the keywords' field.  Because of the
distinct field delimiters, if we search for =-denote= we only match
the first instance while =_denote= targets the second one.  When
sorting through your notes, this kind of specificity is
invaluable---and you get it for free from the file names alone!
Similarly, a search for ==1= will show all notes that are related to
each other by virtue of their signature.

Users can get a lot of value out of this simple yet effective
arrangement, even if they have no knowledge of regular expressions.
One thing to consider, for maximum effect, is to avoid using
multi-word keywords as those can get hyphenated like the title and
will thus interfere with the above: either set the user option
~denote-allow-multi-word-keywords~ to nil or simply insert single
words at the relevant prompts.

** Define a completely custom identifier scheme
:PROPERTIES:
:CUSTOM_ID: h:3048f558-7d84-45d6-9ef2-53055483e801
:END:

[ DEVELOPER NOTE: This is for advanced users. If you really need
  custom identifiers but are not sure how to proceed, please ask and I
  will help you. ]

By default, the Denote identifier consists of the date and time in a
compact format ([[#h:4e9c7512-84dc-4dfb-9fa9-e15d51178e5d][The file-naming scheme]]). Denote, however, can work
with identifiers of an arbitrary format, provided each identifier is
unique. Any string will do.

#+vindex: denote-get-identifier-function
The variable ~denote-get-identifier-function~ specifies the function
that Denote uses to derive a new identifier. The return value is a
string. This function is called while creating new files and when
renaming an existing file:

- [[#h:17896c8c-d97a-4faa-abf6-31df99746ca6][Points of entry]]
- [[#h:532e8e2a-9b7d-41c0-8f4b-3c5cbb7d4dca][Renaming files]]

#+vindex: denote-used-identifiers
The function assigned to ~denote-get-identifier-function~ takes two
arguments: an initial identifier and a date. The initial identifier is
used as a reference to derive a unique variant of it (e.g. to keep
incrementing seconds while keeping the rest of the date+time the
same). Existing identifiers are stored in the variable
~denote-used-identifiers~. If the initial identifier is nil or an
identifier cannot be derived from it, then the date can be used
instead. The date has the same format as ‘current-time’. When it is
nil, the ‘current-time’ is used.

In the following code block, we provide an example of an identifier
scheme that encodes information related to publications: the year, the
edition, the author or authors, the format (e.g. book or paper), and
the publisher. For users who maintain a library of academic works, for
example, this kind of identifier is more useful than the default
date+time scheme.

*** A custom identifier that is a simple incrementing number scheme
:PROPERTIES:
:CUSTOM_ID: h:8b8a4fa9-09fe-4d5c-a003-8808fe292e8b
:END:

This is a sample implementation of custom Denote identifiers ([[#h:3048f558-7d84-45d6-9ef2-53055483e801][Define a completely custom identifier scheme]]).

In its simplest form, a custom Denote identifier can be an integer
that is incremented each time a new file name is produced. In the
following code block, ~my~denote-get-identifier~ is the function we
bind to the variable ~denote-get-identifier-function~, which then
makes Denote use the custom identifier scheme.

#+begin_src emacs-lisp
(setq denote-get-identifier-function #'my-denote-get-identifier)

(defun my-denote--get-all-used-ids ()
  (when-let* ((ids (make-hash-table :test 'equal))
              (files (denote-directory-files nil nil nil nil :has-identifier))
              (file-names (mapcar #'file-name-nondirectory files))
              (names (append file-names (denote--buffer-file-names))))
    (dolist (name names)
      (when-let* ((id (denote-retrieve-filename-identifier name)))
        (puthash id t ids)))
    ids))

(defun my-denote-get-identifier (initial-identifier _date)
  (let ((identifiers (or denote-used-identifiers (my-denote--get-all-used-ids))))
    (cond
     ((and initial-identifier (not (gethash initial-identifier identifiers)))
      initial-identifier)
     (t
      (number-to-string
       (let ((keys nil))
         ;; NOTE 2025-09-19: The `string-to-number' is done with the
         ;; assumption that this is always an integer.  It will break
         ;; with the default Denote identifier scheme or, indeed,
         ;; anything that is not strictly numeric.
         (when identifiers (maphash (lambda (key value) (push (string-to-number key) keys)) identifiers))
         (if keys
             (+ (apply #'max keys) 1)
           1)))))))



;; And this is for testing purposes

;; (let ((denote-directory "/tmp/"))
;;   (my-denote-get-identifier nil nil))
;;
;; (let* ((denote-used-identifiers (make-hash-table :test #'equal))
;;        (_ (progn
;;             (puthash "1" 1 denote-used-identifiers)
;;             (puthash "2" 2 denote-used-identifiers)
;;             (puthash "3" 3 denote-used-identifiers))))
;;   (my-denote-get-identifier "1" nil))
#+end_src

An alternative for the above:

#+begin_src emacs-lisp
(defun my-denote--find-first-unused-id-as-number (id)
  (while (gethash id denote-used-identifiers)
    (setq id (number-to-string (1+ (string-to-number id)))))
  id)

(defun my-denote-generate-identifier-as-number (initial-identifier _date)
  (let ((denote-used-identifiers (or denote-used-identifiers (denote--get-all-used-ids))))
    (cond (;; Always use the supplied initial-identifier if possible,
           ;; regardless of format.
           (and initial-identifier
                (not (gethash initial-identifier denote-used-identifiers)))
           initial-identifier)
          (;; If the supplied initial-identifier is already used, but
           ;; it has the right format, make is unique.
           (and initial-identifier
                (string-match-p "[1-9][0-9]*" initial-identifier))
           (my-denote--find-first-unused-id-as-number initial-identifier))
          (;; Else, the supplied initial-identifier is nil or it is
           ;; already used or it does not match the supplied
           ;; format. Ignore it and generate a valid identifier with
           ;; the right format.
           t
           (my-denote--find-first-unused-id-as-number "1")))))
#+end_src

*** A custom identifier that is a simple string given at the prompt each time
:PROPERTIES:
:CUSTOM_ID: h:197f83af-6149-4262-a186-14d0eab24f1e
:END:

This is a sample implementation of custom Denote identifiers ([[#h:3048f558-7d84-45d6-9ef2-53055483e801][Define a completely custom identifier scheme]]).

While it is possible to implement a certain automatic scheme for the
Denote identifier, users may prefer to have a prompt each time that
asks them for a simple string which is then used as-is. This can be
done by modifying the user option ~denote-prompts~ to include the
=identifier= in the list of file name components to prompt for ([[#h:f9204f1f-fcee-49b1-8081-16a08a338099][The ~denote-prompts~ option]]).

For example:

#+begin_src emacs-lisp
;; The default is '(title keywords)
(setq denote-prompts '(identifier title keywords))
#+end_src

With the above, each time Denote needs to produce a new file name it
will prompt for the identifier. Note that it is then up to the user to
guarantee the uniqueness of the resulting identifiers. With this code,
Denote will fall back to using the current date as the identifier if
the provided string is not yielding a unique match.

In practice, the identifier prompt is a useful tool for wrapper
functions that need to do something special in a given context. For
example, in a folder with some ancient photos the user wants to have
an identifier scheme that is =PLACE+PEOPLE+N= where it is easier to
prompt for that value each time than write some extra code to do the
work. To this end, here is a sample wrapper function of ~denote-rename-file~:

#+begin_src emacs-lisp
(defun my-denote-rename-file-with-identifier-prompt ()
  (interactive)
  (let ((denote-prompts '(identifier title keywords)))
    (call-interactively 'denote-rename-file)))
#+end_src

*** A custom identifier to include the day of the week as a capital letter
:PROPERTIES:
:CUSTOM_ID: h:5bd49896-b0d4-4176-ad7b-27285182bdb2
:END:

The default Denote identifier is a compact version of the date and
time. The letter =T= is placed between the two to delimit where the
date ends and the time starts. This =T= does not have any special
meaning in itself. Users may prefer to have other letters there to
represent the day of the week. For example, Monday is =A=, Tuesday is
=B=, and so on.

Here is a function that takes a number or numeric string argument and
returns the corresponding capital letter for the day of the week. We
will see further below how this function goes together with the rest
of the code necessary for a custom identifier scheme.

#+begin_src emacs-lisp
(defun my-denote-get-day-of-week-as-alpha (day)
  "Return the corresponding capital letter for DAY.
DAY is a string holding a number, as the return value of the %u
specifier in `format-time-string'.

If DAY is a number, convert it to a string and then return its
corresponding letter."
  (pcase (if (numberp day) (number-to-string day) day)
    ("1" "A")
    ("2" "B")
    ("3" "C")
    ("4" "D")
    ("5" "E")
    ("6" "F")
    ("7" "G")
    (_ (error "The day `%S' is not among 1-7" day))))
#+end_src

What we then need is to have a variant of the standard ~denote-date-identifier-format~
where the letter =T= is replaced by the =%u= ~format-time-string~
specifier. That is what gives us the numeric representation of the day
of the week. Then we copy the default ~denote-generate-identifier-as-date~
and modify it to use our format, making the small adjustments
necessary to recreate the identifier as one string.

Putting it all together:

#+begin_src emacs-lisp
(setq denote-get-identifier-function #'my-denote-generate-identifier-as-date)

(defun my-denote-get-day-of-week-as-alpha (day)
  "Return the corresponding capital letter for DAY.
DAY is a string holding a number, as the return value of the %u
specifier in `format-time-string'.

If DAY is a number, convert it to a string and then return its
corresponding letter."
  (pcase (if (numberp day) (number-to-string day) day)
    ("1" "A")
    ("2" "B")
    ("3" "C")
    ("4" "D")
    ("5" "E")
    ("6" "F")
    ("7" "G")
    (_ (error "The day `%S' is not among 1-7" day))))

(defconst my-denote-date-identifier-format
  (replace-regexp-in-string "T" " %u " denote-date-identifier-format t))

(defun my-denote-format-date (date)
  "Format DATE using `my-denote-date-identifier-format'."
  (pcase-let* ((identifier-string (format-time-string my-denote-date-identifier-format date))
               (`(,date ,day-of-week ,time) (split-string identifier-string))
               (day-as-letter (my-denote-get-day-of-week-as-alpha day-of-week)))
    (concat date day-as-letter time)))

(defun my-denote-generate-identifier-as-date (initial-identifier date)
  "Generate an identifier based on DATE.

If INITIAL-IDENTIFIER is not already used, return it.  Else, if it is
possible to derive an identifier from it, return this identifier.

Else, use the DATE.  If it is nil, use `current-time'.

Slightly modified version of `denote-generate-identifier-as-date'."
  (let ((denote-used-identifiers (or denote-used-identifiers (denote--get-all-used-ids))))
    (cond ((and initial-identifier
                (not (gethash initial-identifier denote-used-identifiers)))
           initial-identifier)
          ((and initial-identifier
                (string-match-p denote-date-identifier-regexp initial-identifier)
                (date-to-time initial-identifier))
           (denote--find-first-unused-id-as-date initial-identifier))
          (t
           (denote--find-first-unused-id-as-date
            (my-denote-format-date (or date (current-time))))))))
#+end_src

*** A custom identifier to encode publisher data
:PROPERTIES:
:CUSTOM_ID: h:f92cd454-51f4-4403-9061-3b2efaef2851
:END:

This is a sample implementation of custom Denote identifiers ([[#h:3048f558-7d84-45d6-9ef2-53055483e801][Define a completely custom identifier scheme]]).

This custom identifier cannot be derived programmatically though, so
the function ~my-denote-get-identifier~ makes a series of prompts to
get the relevant data. Then it joins them all together with the
current date to create a unique identifier. The helper function
~my-denote-custom-identifier--make-unique-identifier~ makes sure to
make small tweaks to the "current date" part of this identifier so
that it is always unique.

We can always flesh out this example with, for example, prompts that
leverage ~completing-read~, though the point is to show how custom
identifiers can be implemented in full. Everything else Denote does
with identifiers, namely, links and backlinks, should work as
intended.

Good luck!

#+begin_src emacs-lisp
;; NOTE 2025-09-18: This is for testing the following custom code.
;; The dates will need to be updated to match the test day.
;;
;; (let* ((denote-used-identifiers (make-hash-table :test #'equal))
;;        (_ (progn
;;             (puthash "2000E1AprotFbookPmaxT20250918" t denote-used-identifiers)
;;             (puthash "2000E1AprotFbookPmaxT20250919" t denote-used-identifiers)
;;             (puthash "2000E1AprotFbookPmaxT20250920" t denote-used-identifiers))))
;;   (my-denote-get-identifier "2000E1AprotFbookPmaxT20250918" nil))
;;
;; (let* ((denote-used-identifiers (make-hash-table :test #'equal))
;;        (_ (progn
;;             (puthash "2000E1AprotFbookPmaxT20250918" t denote-used-identifiers)
;;             (puthash "2000E1AprotFbookPmaxT20250919" t denote-used-identifiers)
;;             (puthash "2000E1AprotFbookPmaxT20250920" t denote-used-identifiers))))
;;   (my-denote-custom-identifier--make-unique-identifier "2000E1AprotFbookPmax" (format-time-string "%Y%m%d") denote-used-identifiers))




;; The code herein is a custom function for use with `denote-get-identifier-function':
(setq denote-get-identifier-function #'my-denote-get-identifier)

(defun my-denote-custom-identifier--make-unique-identifier (base-identifier date-string identifiers)
  (let* ((current-date-string date-string)
         (id (format "%sT%s" base-identifier current-date-string)))
    (while (gethash id identifiers)
      (let* ((year (string-to-number (substring current-date-string 0 4)))
             (month (string-to-number (substring current-date-string 4 6)))
             (day (string-to-number (substring current-date-string 6 8)))
             (time (encode-time 0 0 0 day month year))
             (next-day-time (seconds-to-time (+ (time-to-seconds time) 86400)))
             (next-date-string (format-time-string "%Y%m%d" next-day-time)))
        (setq current-date-string next-date-string)
        (setq id (format "%sT%s" base-identifier current-date-string))))
    id))

(defvar my-denote-custom-identifier-year-history nil)
(defvar my-denote-custom-identifier-edition-history nil)
(defvar my-denote-custom-identifier-format-history nil)
(defvar my-denote-custom-identifier-publisher-history nil)

(defvar my-denote-custom-identifier-author-history nil
  "Minibuffer history for `my-denote-custom-identifier-author-prompt'.")

;; TODO 2025-09-18: Flesh out the other prompts as well.  Some can
;; benefit from a `completing-read' approach.
(defun my-denote-custom-identifier-author-prompt ()
  "Prompt for one or more authors.
Multiple authors are separated by a space or comma."
  (read-string "Author (space or comma for many): " nil 'my-denote-custom-identifier-author-history))

(defun my-denote-custom-identifier-author-format (author)
  "Format AUTHOR to use an A delimiter before each name."
  (let ((authors (split-string author "[ ,]+" t "[\s\f\t\n\r\v]+")))
    (format "A%s" (mapconcat #'identity authors "A"))))

(defun my-denote-get-identifier (initial-identifier date)
  (let ((denote-used-identifiers (or denote-used-identifiers (denote--get-all-used-ids))))
    (cond
     ((and initial-identifier (not (gethash initial-identifier denote-used-identifiers)))
      initial-identifier)
     (t
      (let ((base-id (concat
                      (read-string "Year: " nil 'my-denote-custom-identifier-year-history)
                      "E" (read-string "Edition: " nil 'my-denote-custom-identifier-edition-history)
                      (my-denote-custom-identifier-author-format (my-denote-custom-identifier-author-prompt))
                      "F" (read-string "Format: " nil 'my-denote-custom-identifier-format-history)
                      "P" (read-string "Publisher: " nil 'my-denote-custom-identifier-publisher-history))))
        (my-denote-custom-identifier--make-unique-identifier
         base-id
         (format-time-string "%Y%m%d" (or date (current-time)))
         denote-used-identifiers))))))
#+end_src

* Front matter
:PROPERTIES:
:CUSTOM_ID: h:13218826-56a5-482a-9b91-5b6de4f14261
:END:

Notes have their own "front matter".  This is a block of data at the top
of the file, with no empty lines between the entries, which is
automatically generated at the creation of a new note.  The front matter
includes the title and keywords (aka "tags" or "filetags", depending on
the file type) which the user specified at the relevant prompt, as well
as the date and unique identifier, which are derived automatically.

This is how it looks for Org mode (when ~denote-file-type~ is nil or the
=org= symbol):

#+begin_example
#+title:      This is a sample note
#+date:       [2022-06-30 Thu 16:09]
#+filetags:   :denote:testing:
#+identifier: 20220630T160934
#+end_example

For Markdown with YAML (~denote-file-type~ has the =markdown-yaml=
value), the front matter looks like this:

#+begin_example
---
title:      "This is a sample note"
date:       2022-06-30T16:09:58+03:00
tags:       ["denote", "testing"]
identifier: "20220630T160958"
---
#+end_example

For Markdown with TOML (~denote-file-type~ has the =markdown-toml=
value), it is:

#+begin_example
+++
title      = "This is a sample note"
date       = 2022-06-30T16:10:13+03:00
tags       = ["denote", "testing"]
identifier = "20220630T161013"
+++
#+end_example

And for plain text (~denote-file-type~ has the =text= value), we have
the following:

#+begin_example
title:      This is a sample note
date:       2022-06-30
tags:       denote  testing
identifier: 20220630T161028
---------------------------
#+end_example

#+vindex: denote-date-format
The format of the date in the front matter is controlled by the user
option ~denote-date-format~.  When nil, Denote uses a file-type-specific
format:

- For Org, an inactive timestamp is used, such as
  =[2022-06-30 Wed 15:31]=.

- For Markdown, the RFC3339 standard is applied:
  =2022-06-30T15:48:00+03:00=.

- For plain text, the format is that of ISO 8601: =2022-06-30=.

If the value is a string, ignore the above and use it instead.  The
string must include format specifiers for the date.  These are described
in the doc string of ~format-time-string~..

** Change the front matter format
:PROPERTIES:
:CUSTOM_ID: h:7f918854-5ed4-4139-821f-8ee9ba06ad15
:END:

Per Denote's design principles, the code is hackable.  All front matter
is stored in variables that are intended for public use.  We do not
declare those as "user options" because (i) they expect the user to have
some degree of knowledge in Emacs Lisp and (ii) implement custom code.

[ NOTE for tinkerers: code intended for internal use includes double
  hyphens in its symbol.  "Internal use" means that it can be changed
  without warning and with no further reference in the change log.  Do
  not use any of it without understanding the consequences. ]

The variables which hold the front matter format are:

#+vindex: denote-org-front-matter
- ~denote-org-front-matter~

#+vindex: denote-text-front-matter
- ~denote-text-front-matter~

#+vindex: denote-toml-front-matter
- ~denote-toml-front-matter~

#+vindex: denote-yaml-front-matter
- ~denote-yaml-front-matter~

These variables have a string value with specifiers that are used by the
~format~ function.  The formatting operation passes four arguments which
include the values of the given entries.  If you are an advanced user
who wants to edit this variable to affect how front matter is produced,
consider using something like =%2$s= to control where the Nth argument
is placed.

When editing the value, make sure to:

1. Not use empty lines inside the front matter block.

2. Insert at least one empty line after the front matter block and do
   not use any empty line before it.

These help with consistency and might prove useful if we ever need to
operate on the front matter as a whole.

With those granted, below are some examples.  The approach is the same
for all variables.

#+begin_src emacs-lisp
;; Like the default, but upcase the entries
(setq denote-org-front-matter
  "#+TITLE:      %s
#+DATE:       %s
#+FILETAGS:   %s
#+IDENTIFIER: %s
\n")

;; Change the order (notice the %N$s notation)
(setq denote-org-front-matter
  "#+title:      %1$s
#+filetags:   %3$s
#+date:       %2$s
#+identifier: %4$s
\n")

;; Remove the date
(setq denote-org-front-matter
  "#+title:      %1$s
#+filetags:   %3$s
#+identifier: %4$s
\n")

;; Remove the date and the identifier
(setq denote-org-front-matter
  "#+title:      %1$s
#+filetags:   %3$s
\n")
#+end_src

Note that ~setq~ has a global effect: it affects the creation of all new
notes.  Depending on the workflow, it may be preferrable to have a
custom command which ~let~ binds the different format.  We shall not
provide examples at this point as this is a more advanced feature and we
are not yet sure what the user's needs are.  Please provide feedback and
we shall act accordingly.

** Regenerate front matter
:PROPERTIES:
:CUSTOM_ID: h:54b48277-e0e5-4188-ad54-ef3db3b7e772
:END:

As part of version 4.0.0, the command ~denote-add-front-matter~ is
superseded by ~denote-rename-file~ and related ([[#h:532e8e2a-9b7d-41c0-8f4b-3c5cbb7d4dca][Renaming files]]). Those
commands will add missing front matter or rewrite the modified lines
of existing front matter.

* Linking notes
:PROPERTIES:
:CUSTOM_ID: h:fc913d54-26c8-4c41-be86-999839e8ad31
:END:

Denote offers several commands for linking between notes. Those use
the =denote:= hyperlink type. There are two types of links supported
by Denote:

- Direct links :: A direct link points to a file inside the
  ~denote-directory~. The link is constructed by using the =denote:=
  prefix and the target file's identifier ([[#h:4e9c7512-84dc-4dfb-9fa9-e15d51178e5d][The file-naming scheme]]).
  This looks like =denote:20250328T075526=. The syntax of a link
  depends on the file type. For example, in Org and plain text links look like
  =[[denote:20250328T075526][The title of the target file]]=, while in
  Markdown they are written as =[The title of the target file](denote:20250328T075526)=.

- Query links :: The =denote:= hyperlink type also supports special
  qualifiers that change how the target of the link is interpreted.
  The qualifier is a special token than tells Denote how to treat the
  target of the link. It is written thus =denote:TOKEN:QUERY=. There
  are two kinds of tokens: =query-contents= and =query-filenames=.
  Those determine how the query terms are used. As their names
  suggest, these two tokens trigger a search in (i) the file contents
  of all readable files or (ii) in the file names only. They are, in
  other words, counterparts of the Unix ~grep~ and ~find~ programs,
  respectively.

The following sections cover all the details ([[#h:4f354db1-aa78-47fd-ac60-c3d1e0f0b0a4][Why are some Org links opening outside Emacs?]]).

** Add a single direct link using a file name prompt
:PROPERTIES:
:CUSTOM_ID: h:5e5e3370-12ab-454f-ba09-88ff44214324
:END:

#+findex: denote-link
#+findex: denote-insert-link
The ~denote-link~ command (alias ~denote-insert-link~) inserts a link
at point to a file selected at the minibuffer prompt. Links are
formatted depending on the file type of the current note. In Org and
plain text buffers, links are formatted thus: =[[denote:IDENTIFIER][DESCRIPTION]]=.
While in Markdown they are expressed as =[DESCRIPTION](denote:IDENTIFIER)=.

When ~denote-link~ is called with a prefix argument (=C-u= by
default), it formats links like =[[denote:IDENTIFIER]]=, regardless of
file type ([[#h:156c5ea3-147b-4f9d-a404-86a00558c60a][Fontify links in non-Org buffers]]). The user might prefer
its simplicity.

By default, the description of the link is determined thus:

- If the region is active, its text becomes the description of the
  link. In other words, the region text becomes the link.
- If the region is active but has no text, the description is empty
  and so the link is formatted the same way as if using the =C-u=
  prefix argument.
- If there is no region active, the description consists of the target
  file's signature and title, using the former only if it is present.
  The title is retrieved either from the front matter or the file
  name.
- If the target file has no signature, the title is used.

To insert multiple such links at once, use the command
~denote-add-links~ ([[#h:9bec2c83-36ca-4951-aefc-7187c5463f90][Insert links matching a regexp in their file name]]).

If you want to directly link to a single file whose contents match a
given query, then use the command ~denote-link-to-file-with-contents~
([[#h:25a983ca-049e-43d4-8f6e-06a2325e2c3c][Adding a direct link to a file whose contents include the given query]]).

#+vindex: denote-faces-link
Links are styled with the ~denote-faces-link~ face, which looks
exactly like an ordinary link by default.

[ We optionally support direct links to a file followed by an extra
  target to an Org headings ([[#h:d99de1fb-b1b7-4a74-8667-575636a4d6a4][The ~denote-org-store-link-to-heading~ user option]]).
  Other file types do not have the features of Org, so we cannot
  generalise this. ]

** Add a direct link to a file whose contents include the given query
:PROPERTIES:
:CUSTOM_ID: h:25a983ca-049e-43d4-8f6e-06a2325e2c3c
:END:

#+findex: denote-link-to-file-with-contents
The ~denote-link~ command that we covered before prompts to select a
file among those in the ~denote-directory~ ([[#h:5e5e3370-12ab-454f-ba09-88ff44214324][Adding a single direct link using a file name prompt]]).
The match is done against the file's name. Users may, however, be
interested to create a link to a file whose contents include some
text, regardless of how the file name is called. To this end, the
command ~denote-link-to-file-with-contents~, (i) prompts for a query
which is a plain string or regular expression, (ii) if there are
matching files, asks to select one among them, and (iii) inserts the
direct link at point.

When called with an optional prefix argument (=C-u= by default), the
command ~denote-link-to-file-with-contents~ creates a link that does
not include a description for the target file: it just has the file's
identifier (same as with ~denote-link~).

The command ~denote-link-to-file-with-contents~ is the counterpart of
~denote-link-to-all-files-with-contents~ ([[#h:299d3aeb-9946-489e-bd91-e06f8c4ae2a9][Insert links to all files matching a query in their contents]]).

** Add a query link
:PROPERTIES:
:CUSTOM_ID: h:d9a84289-2f73-4ef9-b4f0-9a0aa3e9bf0d
:END:

As noted in the introduction to this section of the manual, the
=denote:= hyperlink type supports query links ([[#h:fc913d54-26c8-4c41-be86-999839e8ad31][Linking notes]]). Unlike
direct links, they do not point to any given file. Instead, they
trigger a search, whose results are displayed in a separate buffer.

Query links are expressed as =denote:TOKEN:QUERY=, where =TOKEN= is
either =query-contents= or =query-filenames=, while =QUERY= is a
string or Emacs regular expression to search for.

The exact syntax of a query link depends on the file type. In Org and
plain text buffers, links are of the form =[[denote:TOKEN:QUERY][QUERY]]=.
In Markdown, they are formatted as  =[QUERY](denote:TOKEN:QUERY)=. In
all cases, the description of the link is the query text itself.

#+findex: denote-query-contents-link
The command ~denote-query-contents-link~ inserts a link at point that
triggers a search in the file contents of all readable documents in
the ~denote-directory~ ([[#h:435592bc-e896-429f-a599-9f1bcd5ab9b8][Interact with the links buffer]]). This is the
equivalent of the Unix ~grep~ command and uses the built-in Emacs Xref
interface ([[#h:893eec49-d7be-4603-bcff-fcc247244011][Speed up backlinks' or query links' buffer creation?]]).
Matches are displayed in a separate buffer, highlighting the exact
text while showing its context.

#+findex: denote-query-filenames-link
The command ~denote-query-filenames-link~ creates a link at point that
initiates a search across file names in the ~denote-directory~. This
is the equivalent of the Unix ~find~ command. Results are placed in a
Dired buffer ([[#h:9fe01e63-f34f-4479-8713-f162a5ca865e][Display filtered and sorted files with ~denote-sort-dired~]]).

#+vindex: denote-query-links-display-buffer-action
The user option ~denote-query-links-display-buffer-action~ controls
the placement of query link buffers. By default, they are designed to
appear below the current window.

#+vindex: denote-faces-query-link
Query links are styled with the ~denote-faces-query-link~ face, which
looks a bit different that ~denote-faces-link~ (though this depends on
the active theme).

** Insert links to all files matching a query in their file name
:PROPERTIES:
:CUSTOM_ID: h:9bec2c83-36ca-4951-aefc-7187c5463f90
:END:

#+findex: denote-add-links
The command ~denote-add-links~ adds links at point to all file names
in the ~denote-directory~ that match a regular expression or plain
string. This is similar to the ~denote-link~ command, which
establishes a direct link to a specified file ([[#h:5e5e3370-12ab-454f-ba09-88ff44214324][Adding a single direct link]]).
Links to files whose names match the given search terms are inserted
as a typographic list, such as:

#+begin_example
- link1
- link2
- link3
#+end_example

Each link is formatted according to the file type of the current note,
as explained further above about the ~denote-link~ command.  The current
note is excluded from the matching entries (adding a link to itself is
pointless).

When called with a prefix argument (=C-u=) ~denote-add-links~ will
format all links as =[[denote:IDENTIFIER]]=, hence a typographic list:

#+begin_example
- [[denote:IDENTIFIER-1]]
- [[denote:IDENTIFIER-2]]
- [[denote:IDENTIFIER-3]]
#+end_example

Same examples of a regular expression that can be used with this
command:

- =journal= match all files which include =journal= anywhere in their
  name.

- =_journal= match all files which include =journal= as a keyword.

- =^2022.*_journal= match all file names starting with =2022= and
  including the keyword =journal=.

- =\.txt= match all files including =.txt=.  In practical terms, this
  only applies to the file extension, as Denote automatically removes
  dots (and other characters) from the base file name.

If files are created with ~denote-sort-keywords~ as non-nil (the
default), then it is easy to write a regexp that includes multiple
keywords in alphabetic order:

- =_denote.*_package= match all files that include both the =denote= and
  =package= keywords, in this order.

- =\(.*denote.*package.*\)\|\(.*package.*denote.*\)= is the same as
  above, but out-of-order.

Remember that regexp constructs only need to be escaped once (like =\|=)
when done interactively but twice when called from Lisp.  What we show
above is for interactive usage.

Links are created only for files which qualify as a "note" for our
purposes ([[#h:fc913d54-26c8-4c41-be86-999839e8ad31][Linking notes]]).

** Insert links to all files matching a query in their contents
:PROPERTIES:
:CUSTOM_ID: h:299d3aeb-9946-489e-bd91-e06f8c4ae2a9
:END:

#+findex: denote-link-to-all-files-with-contents
The aforementioned ~denote-add-links~ command takes a query that
matches it against file names ([[#h:9bec2c83-36ca-4951-aefc-7187c5463f90][Insert links to all files matching a query in their file name]]).
It then creates a typographic list (bullet list) with direct links to
all the matching files. Users who wish to achieve the same result but
have the query be matched against file contents (not file names), can
use the command ~denote-link-to-all-files-with-contents~.

The command ~denote-link-to-all-files-with-contents~ is the
counterpart of ~denote-link-to-file-with-contents~ ([[#h:25a983ca-049e-43d4-8f6e-06a2325e2c3c][Add a direct link to a file whose contents include the given query]]).

** The ~denote-open-link-function~ user option
:PROPERTIES:
:CUSTOM_ID: h:6aa22a2d-3338-433e-ab9f-ba272417aab9
:END:

#+vindex: denote-open-link-function
The user option ~denote-open-link-function~ specifies the function
used by Denote to open the file of a link. The default value opens the
file in the other window. Another common value is the function
~find-file~, which will open the file in the current window. Users may
also specify a function of their choosing.

Note that this is relevant in buffers other than Org mode because Org
has its own mechanism for how to open links (read the documentation of
the command ~org-open-at-point~).

** The ~denote-org-store-link-to-heading~ user option
:PROPERTIES:
:CUSTOM_ID: h:d99de1fb-b1b7-4a74-8667-575636a4d6a4
:END:

#+vindex: denote-org-store-link-to-heading
The user option ~denote-org-store-link-to-heading~ determines whether
~org-store-link~ links to the current Org heading.

[ Remember that what ~org-store-link~ does is merely collect a link.  To
  actually insert it, use the command ~org-insert-link~.  Note that
  ~org-capture~ uses ~org-store-link~ internally when it needs to store
  a link.  ]

When the value is nil, the Denote handler for ~org-store-link~ produces
links only to the current file (by using the file's identifier).  For
example:

: [[denote:20240118T060608][Some test]]

If the value is ~context~, the link consists of the file's identifier
and the text of the current heading, like this:

: [[denote:20240118T060608::*Heading text][Some test::Heading text]].

However, if there already exists a =CUSTOM_ID= property for the
current heading, this is always given priority and is used instead of
the context.

If the value is ~id~ or, for backward-compatibility, any other non-nil
value, then Denote will use the standard Org mechanism of the
=CUSTOM_ID= property to create a unique link to the heading. If the
heading does not have a =CUSTOM_ID=, it creates it and includes it in
its =PROPERTIES= drawer. If a =CUSTOM_ID= exists, it takes it as-is.
The result is like this:

 : [[denote:20240118T060608::#h:eed0fb8e-4cc7-478f][Some test::Heading text]]

The value of the =CUSTOM_ID= is determined by the Org user option
~org-id-method~. The sample shown above uses the default UUID
infrastructure (though I deleted a few characters to not get
complaints from the byte compiler about long lines in the doc
string...).

Note that this option does not affect how Org behaves with regard to
~org-id-link-to-org-use-id~. If that user option is set to create =ID=
properties, then those will be created by Org even if the Denote link
handler will take care to not use/store the =ID= value. Concretely,
users who never want =ID= properties under their headings should keep
~org-id-link-to-org-use-id~ in its nil value.

Context links are easier to break than those with a =CUSTOM_ID= in
cases where either the heading text changes or there is another
heading that matches that text. The potential advantage of context
links is that they do not require a =PROPERTIES= drawer.

When visiting a link to a heading, Org opens the Denote file and then
navigates to that heading.

[ This feature only works in Org mode files, as other file types do
  not have a linking mechanism that handles unique identifiers for
  headings or other patterns to jump to. If ~org-store-link~ is
  invoked in one such file, it captures only the Denote identifier of
  the file, even if this user option is set to a non-nil value. ]

** Adding direct links to files matching contents
:PROPERTIES:
:CUSTOM_ID: h:28cb8d14-cf56-4d73-b126-8ff269dbaa64
:END:

** Insert links from marked files in Dired
:PROPERTIES:
:CUSTOM_ID: h:9cbb692e-5d8a-44a6-9193-899a07872a07
:END:

#+findex: denote-link-dired-marked-notes
The command ~denote-link-dired-marked-notes~ is similar to
~denote-add-links~ in that it inserts in the buffer a typographic list
of links to Denote notes ([[#h:9bec2c83-36ca-4951-aefc-7187c5463f90][Insert links matching a regexp]]).  Though
instead of reading a regular expression, it lets the user mark files
in Dired and link to them.  This should be easier for users of all
skill levels, instead of having to write a potentially complex regular
expression.

If there are multiple buffers that visit a Denote note, this command
will ask to select one among them, using minibuffer completion.  If
there is only one buffer, it will operate in it outright.  If there are
no buffers, it will produce an error.

With optional =ID-ONLY= as a prefix argument (=C-u= by default), the
command inserts links with just the identifier, which is the same
principle as with ~denote-link~ and others ([[#h:5e5e3370-12ab-454f-ba09-88ff44214324][Adding a single link]]).

The command ~denote-link-dired-marked-notes~ is meant to be used from a
Dired buffer.

As always, links are created only for files which qualify as a "note"
for our purposes ([[#h:fc913d54-26c8-4c41-be86-999839e8ad31][Linking notes]]).

#+findex: denote-dired-link-marked-notes
The ~denote-dired-link-marked-notes~ is an alias for ~denote-link-dired-marked-notes~.

** Link to an existing note or create a new one
:PROPERTIES:
:CUSTOM_ID: h:b6056e6b-93df-4e6b-a778-eebd105bac46
:END:

In one's note-taking workflow, there may come a point where they are
expounding on a certain topic but have an idea about another subject
they would like to link to ([[#h:fc913d54-26c8-4c41-be86-999839e8ad31][Linking notes]]).  The user can always rely on
the other linking facilities we have covered herein to target files that
already exist.  Though they may not know whether they already have notes
covering the subject or whether they would need to write new ones.  To
this end, Denote provides two convenience commands:

#+findex: denote-link-after-creating
+ ~denote-link-after-creating~ :: Create new note in the background and
  link to it directly.

  Use ~denote~ interactively to produce the new note.  Its doc string or
  this manual explains which prompts will be used and under what
  conditions ([[#h:6a92a8b5-d766-42cc-8e5b-8dc255466a23][Standard note creation]]).

  With optional =ID-ONLY= as a prefix argument (this is the =C-u= key,
  by default) create a link that consists of just the identifier.  Else
  try to also include the file's title.  This has the same meaning as in
  ~denote-link~ ([[#h:5e5e3370-12ab-454f-ba09-88ff44214324][Adding a single link]]).

  IMPORTANT NOTE: Normally, ~denote~ does not save the buffer it
  produces for the new note ([[#h:bf80f4cd-6f56-4f7c-a991-8573161e4511][The ~denote-save-buffer-after-creation~ option]]).
  This is a safety precaution to not write to disk unless the user
  wants it (e.g. the user may choose to kill the buffer, thus
  cancelling the creation of the note). However, for this command the
  creation of the note happens in the background and the user may miss
  the step of saving their buffer. We thus have to save the buffer in
  order to (i) establish valid links, and (ii) retrieve whatever front
  matter from the target file.

#+findex: denote-link-after-creating-with-command
+ ~denote-link-after-creating-with-command~ :: This command is like
  ~denote-link-after-creating~ except it prompts for a note-creating
  command ([[*Points of entry][Points of entry]]).  Use this to, for example, call
  ~denote-signature~ so that the newly created note has a signature as
  part of its file name.  Optional =ID-ONLY= has the same meaning as
  in the command ~denote-link-after-creating~.

#+findex: denote-link-or-create
+ ~denote-link-or-create~ :: Use ~denote-link~ on =TARGET= file,
  creating it if necessary.

  If =TARGET= file does not exist, call ~denote-link-after-creating~
  which runs the ~denote~ command interactively to create the file.  The
  established link will then be targeting that new file.

  If =TARGET= file does not exist, add the user input that was used to
  search for it to the history of the ~denote-file-prompt~.  The user
  can then retrieve and possibly further edit their last input, using
  it as the newly created note's actual title.  At the ~denote-file-prompt~
  type =M-p= with the default key bindings, which calls ~previous-history-element~.

  With optional =ID-ONLY= as a prefix argument create a link with just
  the file's identifier.  This has the same meaning as in ~denote-link~.

  This command has the alias ~denote-link-to-existing-or-new-note~,
  which helps with discoverability.

In all of the above, an optional prefix argument (=C-u= by default)
creates a link that consists of just the identifier.  This has the
same meaning as in the regular ~denote-link~ command.

Denote provides similar functionality for opening an existing note or
creating a new one ([[#h:ad91ca39-cf10-4e16-b224-fdf78f093883][Open an existing note or create it if missing]]).

** The backlinks' buffer
:PROPERTIES:
:CUSTOM_ID: h:c73f1f68-e214-49d5-b369-e694f6a5d708
:END:

[ Older versions of Denote had two types of formatting for the
  backlinks' buffer. As part of version =4.0.0=, we only support the
  standard Xref view which shows matches in their context. The user
  option ~denote-backlinks-show-context~ is thus removed. ]

#+findex: denote-backlinks
#+findex: denote-show-backlinks-buffer
The command ~denote-backlinks~ (alias ~denote-show-backlinks-buffer~)
produces a bespoke buffer which displays backlinks to the current note
([[#h:435592bc-e896-429f-a599-9f1bcd5ab9b8][Interact with the links buffer]]). A "backlink" is a link back to the
present entry. Backlinks can be generated for any file type that has a
Denote file-naming scheme, such as PDFs, images, and videos, as well
as the regular plain text files.

The backlinks' buffer is, in essence, the equivalent of a Unix ~grep~
command across the ~denote-directory~ ([[#h:893eec49-d7be-4603-bcff-fcc247244011][Speed up backlinks' buffer creation?]]).
It groups matches by file name, while it displays the line on which a
link to the current file occurs together with its context. It looks
like this (plus the appropriate fontification):

#+begin_example
Backlinks to "On being honest" (20220614T130812)
------------------------------------------------

20220614T145606--let-this-glance-become-a-stare__journal.txt
37: growing into it: [[denote:20220614T130812][On being honest]].
64: As I said in [[denote:20220614T130812][On being honest]] I have never
20220616T182958--feeling-butterflies-in-your-stomach__journal.txt
62: indifference.  In [[denote:20220614T130812][On being honest]] I alluded
#+end_example

Note that the width of the lines in the context depends on the
underlying file. In the above example, the lines are split at the
~fill-column~. Long lines will show up just fine. Also note that the
built-in user option ~xref-truncation-width~ can truncate long lines
to a given maximum number of characters.

As with query links, the backlinking facility uses Emacs' built-in
Xref infrastructure ([[#h:d9a84289-2f73-4ef9-b4f0-9a0aa3e9bf0d][Adding a query link]]). On some operating systems,
the user may need to add certain executables to the relevant
environment variable ([[#h:42f6b07e-5956-469a-8294-17f9cf62eb2b][Why do I get "Search failed with status 1" when I search for backlinks?]]).

#+vindex: denote-backlinks-display-buffer-action
The placement of the backlinks' buffer is subject to the user option
~denote-backlinks-display-buffer-action~. Due to the nature of the
underlying ~display-buffer~ mechanism, this inevitably is a relatively
advanced feature. By default, the backlinks' buffer is displayed below
the current window.

Backlinks to the current file can also be visited by using the
minibuffer completion interface with the ~denote-find-backlink~
command or the more powerful ~denote-find-backlink-with-location~
([[#h:1bc2adad-dca3-4878-b9f0-b105d5dec6f4][Visiting linked files via the minibuffer]]).

** Writing metanotes
:PROPERTIES:
:CUSTOM_ID: h:6060a7e6-f179-4d42-a9de-a9968aaebecc
:END:

A "metanote" is an entry that describes other entries who have something
in common.  Writing metanotes can be part of a workflow where the user
periodically reviews their work in search of patterns and deeper
insights.  For example, you might want to read your journal entries from
the past year to reflect on your experiences, evolution as a person, and
the like.

The commands ~denote-add-links~, ~denote-link-dired-marked-notes~ are
suited for this task.

[[#h:9bec2c83-36ca-4951-aefc-7187c5463f90][Insert links matching a regexp]].

[[#h:9cbb692e-5d8a-44a6-9193-899a07872a07][Insert links from marked files in Dired]].

You will create your metanote the way you use Denote ordinarily
(metanotes may have the =metanote= keyword, among others), write an
introduction or however you want to go about it, invoke the command
which inserts multiple links at once (see the above-cited nodes), and
continue writing.

Metanotes can serve as entry points to groupings of individual notes.
They are not the same as a filtered list of files, i.e. what you would
do in Dired or the minibuffer where you narrow the list of notes to a
given query.  Metanotes contain the filtered list plus your thoughts
about it.  The act of purposefully grouping notes together and
contemplating on their shared patterns is what adds value.

Your future self will appreciate metanotes for the function they serve
in encapsulating knowledge, while current you will be equipped with the
knowledge derived from the deliberate self-reflection.

** Visiting linked files via the minibuffer
:PROPERTIES:
:CUSTOM_ID: h:1bc2adad-dca3-4878-b9f0-b105d5dec6f4
:END:

#+findex: denote-find-link
Denote has a major-mode-agnostic mechanism to collect all linked file
references in the current buffer and return them as an appropriately
formatted list.  This list can then be used in interactive commands.
The ~denote-find-link~ is such a command.  It uses minibuffer
completion to visit a file that is linked to from the current note.
The candidates have the correct metadata, which is ideal for
integration with other standards-compliant tools ([[#h:8ed2bb6f-b5be-4711-82e9-8bee5bb06ece][Extending Denote]]).
For instance, a package such as =marginalia= will display accurate
annotations, while the =embark= package will be able to work its magic
such as in exporting the list into a filtered Dired buffer (i.e. a
familiar Dired listing with only the files of the current minibuffer
session).

#+findex: denote-find-backlink
To visit backlinks to the current note via the minibuffer, use
~denote-find-backlink~.  This is an alternative to placing backlinks
in a dedicated buffer ([[#h:c73f1f68-e214-49d5-b369-e694f6a5d708][The backlinks' buffer]]).

#+findex: denote-find-backlink-with-location
As an alternative to ~denote-find-backlink~, the command
~denote-find-backlink-with-location~ shows the complete results of all
backlinks in their context, grouped by file. It prompts to pick one
among them, using minibuffer completion, and then jumps to the
corresponding file at that exact location where the link is.

Think of the ~denote-find-backlink-with-location~ as the
minibuffer-centric variant of the backlinks buffer: the backlinks
buffer sticks around, whereas this one is only available for the
duration of the command. Depending on the scenario, one is more
appropriate than the other.

** Fontify links in non-Org buffers
:PROPERTIES:
:CUSTOM_ID: h:156c5ea3-147b-4f9d-a404-86a00558c60a
:END:

#+findex: denote-fontify-links-mode
Denote links are automatically fontified in Org buffers ([[#h:5e5e3370-12ab-454f-ba09-88ff44214324][Adding a single link]]).
This means that Org recognises the link and applies the relevant
properties to it to make it clickable/actionable. Other major modes,
such as ~markdown-mode~ (for =.md= files) or ~text-mode~ (for =.txt=
files) do not have this feature built into them. Users can still get
the same behaviour as with Org by activating the ~denote-fontify-links-mode~.

The ~denote-fontify-links-mode~ is a buffer-local minor mode. Users can enable
it automatically in plain text files that correspond to denote notes with
something like this:

#+begin_src emacs-lisp
(add-hook 'text-mode-hook #'denote-fontify-links-mode-maybe)
#+end_src

The ~text-mode-hook~ applies to all modes derived from ~text-mode~, including
~markdown-mode~. Though a more explicit setup does no harm:

#+begin_src emacs-lisp
(add-hook 'markdown-mode-hook #'denote-fontify-links-mode-maybe)
#+end_src

Because Org already recognises =denote:= links, the function
~denote-fontify-links-mode-maybe~ will not enable the mode
~denote-fontify-links-mode~ in Org buffers.

#+findex: denote-link-markdown-follow
In files whose major mode is ~markdown-mode~, the default key binding
=C-c C-o= (which calls the command ~markdown-follow-thing-at-point~)
correctly resolves =denote:= links. Interested users can refer to the
function ~denote-link-markdown-follow~ for the implementation details.

** The ~denote-link-description-format~ to format link descriptions
:PROPERTIES:
:CUSTOM_ID: h:f634427c-b451-40e2-993e-e00ac627af68
:END:

The user option ~denote-link-description-format~ controls how the
command ~denote-link~ and related functions create a link description
by default.

The value can be either a function or a string. If it is a function,
it is called with two argument, the file and file type, and should
return a string representing the link description. The default is a
function that returns the active region or the title of the note (with
the signature if present).

For backward compatibility, the function can also take a single
parameter, the given file. In that case, it is responsible for
figuring out the file type in order to return the correct description.

[ The calling convention for the function with two arguments is
  introduced as part of {{{development-version}}}. ]

If the value is a string, it treats specially the following specifiers:

- The =%t= is the Denote =TITLE= in the front matter or the file name.
- The =%T= is the Denote =TITLE= in the file name.
- The =%i= is the Denote =IDENTIFIER= of the file.
- The =%I= is the identifier converted to =DAYNAME, DAYNUM MONTHNUM
  YEAR=.
- The =%d= is the same as =%i= (=DATE= mnemonic).
- The =%D= is a "do what I mean" which behaves the same as =%t= and if
  that returns nothing, it falls back to =%I=, then =%i=.
- The =%d= is the same as =%i= (=DATE= mnemonic).
- The =%s= is the Denote =SIGNATURE= of the file.
- The =%k= is the Denote =KEYWORDS= of the file.
- The =%%= is a literal percent sign.

In addition, the following flags are available for each of the specifiers:

- 0 :: Pad to the width, if given, with zeros instead of spaces.
- - :: Pad to the width, if given, on the right instead of the left.
- < :: Truncate to the width and precision, if given, on the left.
- > :: Truncate to the width and precision, if given, on the right.
- ^ :: Convert to upper case.
- _ :: Convert to lower case.

When combined all together, the above are written thus:

: %<flags><width><precision>SPECIFIER-CHARACTER

Any other text in the string it taken as-is. Users may want, for
example, to include some text that makes Denote links stand out, such
as a =[D]= prefix.

If the region is active, its text is used as the link's description.

* Choose which commands to prompt for
:PROPERTIES:
:CUSTOM_ID: h:98c732ac-da0e-4ebd-a0e3-5c47f9075e51
:END:

#+vindex: denote-commands-for-new-notes
The user option ~denote-commands-for-new-notes~ specifies a list of
commands that are available at the ~denote-command-prompt~.  This
prompt is used by Denote commands that ask the user how to create a
new note, as described elsewhere in this manual:

- [[#h:ad91ca39-cf10-4e16-b224-fdf78f093883][Open an existing note or create it if missing]]
- [[#h:b6056e6b-93df-4e6b-a778-eebd105bac46][Link to a note or create it if missing]]

The default value includes all the basic file-creating commands
([[#h:17896c8c-d97a-4faa-abf6-31df99746ca6][Points of entry]]).  Users may customise this value if (i) they only
want to see fewer options and/or (ii) wish to include their own custom
command in the list ([[#h:11946562-7eb0-4925-a3b5-92d75f1f5895][Write your own convenience commands]]).

* Fontification in Dired
:PROPERTIES:
:CUSTOM_ID: h:337f9cf0-9f66-45af-b73f-f6370472fb51
:END:

#+findex: denote-dired-mode
One of the upsides of Denote's file-naming scheme is the predictable
pattern it establishes, which appears as a near-tabular presentation in
a listing of notes (i.e. in Dired).  The ~denote-dired-mode~ can help
enhance this impression, by fontifying the components of the file name
to make the date (identifier) and keywords stand out.

There are two ways to set the mode.  Either use it for all directories,
which probably is not needed:

#+begin_src emacs-lisp
(add-hook 'dired-mode-hook #'denote-dired-mode)
#+end_src

#+vindex: denote-dired-directories
#+findex: denote-dired-mode-in-directories
Or configure the user option ~denote-dired-directories~ and then set up
the function ~denote-dired-mode-in-directories~:

#+begin_src emacs-lisp
;; We use different ways to specify a path for demo purposes.
(setq denote-dired-directories
      (list denote-directory
            (thread-last denote-directory (expand-file-name "attachments"))
            (expand-file-name "~/Documents/vlog")))

(add-hook 'dired-mode-hook #'denote-dired-mode-in-directories)
#+end_src

#+vindex: denote-dired-directories-include-subdirectories
The user option ~denote-dired-directories-include-subdirectories~
specifies whether the ~denote-dired-directories~ also cover their
subdirectories. By default they do not. Set this option to ~t~ to
include subdirectories as well.

The faces we define for this purpose are:

#+vindex: denote-faces-date
#+vindex: denote-faces-delimiter
#+vindex: denote-faces-extension
#+vindex: denote-faces-keywords
#+vindex: denote-faces-signature
#+vindex: denote-faces-subdirectory
#+vindex: denote-faces-time
#+vindex: denote-faces-title
+ ~denote-faces-date~
+ ~denote-faces-delimiter~
+ ~denote-faces-extension~
+ ~denote-faces-keywords~
- ~denote-faces-signature~
+ ~denote-faces-subdirectory~
+ ~denote-faces-time~
+ ~denote-faces-title~

For more control, we also provide these:

#+vindex denote-faces-year
#+vindex denote-faces-month
#+vindex denote-faces-day
#+vindex denote-faces-hour
#+vindex denote-faces-minute
#+vindex denote-faces-second
+ ~denote-faces-year~
+ ~denote-faces-month~
+ ~denote-faces-day~
+ ~denote-faces-hour~
+ ~denote-faces-minute~
+ ~denote-faces-second~

For the time being, the =diredfl= package is not compatible with this
facility.

The ~denote-dired-mode~ does not only fontify note files that were
created by Denote: it covers every file name that follows our naming
conventions ([[#h:4e9c7512-84dc-4dfb-9fa9-e15d51178e5d][The file-naming scheme]]).  This is particularly useful for
scenaria where, say, one wants to organise their collection of PDFs and
multimedia in a systematic way (and, perhaps, use them as attachments
for the notes Denote produces if you are writing Org notes and are using
its standand attachments' facility).

* Set the prefix of all Denote buffers
:PROPERTIES:
:CUSTOM_ID: h:a3a1a2af-a0b8-420c-acb1-855a7d113e69
:END:

#+vindex: denote-buffer-name-prefix
The user option ~denote-buffer-name-prefix~ specifies the text used as
a prefix of all buffer names generated by Denote. This applies to the
buffer of query links, backlinks, ~denote-grep~, ~denote-dired~, as
well as those affected by ~denote-rename-buffer-mode~:

- [[#h:d9a84289-2f73-4ef9-b4f0-9a0aa3e9bf0d][Add a query link]].
- [[#h:c73f1f68-e214-49d5-b369-e694f6a5d708][The backlinks' buffer]].
- [[#h:e71c9d14-7e88-4386-91d0-9ad249947077][Use ~denote-grep~ to search inside files]].
- [[#h:9fe01e63-f34f-4479-8713-f162a5ca865e][Display filtered and sorted files with ~denote-sort-dired~ or ~denote-dired~]].
- [[#h:3ca4db16-8f26-4d7d-b748-bac48ae32d69][Automatically rename Denote file buffers]].

By default, the value of ~denote-buffer-name-prefix~ is ="[D] "=.
Users can set it to any string they want, such as ="<Denote> "=, or
even an empty string to not have any such prefix.

* Automatically rename Denote file buffers
:PROPERTIES:
:CUSTOM_ID: h:3ca4db16-8f26-4d7d-b748-bac48ae32d69
:END:

#+findex: denote-rename-buffer-mode
The minor mode ~denote-rename-buffer-mode~ provides the means to
automatically rename the buffer of a Denote file upon visiting the
file. This applies both to existing Denote files as well as new ones
([[#h:17896c8c-d97a-4faa-abf6-31df99746ca6][Points of entry]]). Enable the mode thus:

#+begin_src emacs-lisp
(denote-rename-buffer-mode 1)
#+end_src

#+vindex: denote-rename-buffer-function
#+findex: denote-rename-buffer
#+vindex: denote-rename-buffer-format
Buffers are named by applying the function specified in the user
option ~denote-rename-buffer-function~. The default function is
~denote-rename-buffer~: it renames the buffer based on the template
set in the user option ~denote-rename-buffer-format~, combined with
the ~denote-buffer-name-prefix~ ([[#h:a3a1a2af-a0b8-420c-acb1-855a7d113e69][Set the prefix of all Denote buffers]]).
Other fields are explained elsewhere in this manual ([[#h:35507c18-35b1-41b9-9d80-52f54fcef3cb][The denote-rename-buffer-format]]).

Note that renaming a buffer is not the same as renaming a file
([[#h:532e8e2a-9b7d-41c0-8f4b-3c5cbb7d4dca][Renaming files]]). The former is just for convenience inside of Emacs.
Whereas the latter is for writing changes to disk, making them
available to all programs.

** The ~denote-rename-buffer-format~ option
:PROPERTIES:
:CUSTOM_ID: h:35507c18-35b1-41b9-9d80-52f54fcef3cb
:END:

The user option ~denote-rename-buffer-format~ controls how the
function ~denote-rename-buffer~ chooses the name of the
buffer-to-be-renamed. It also affects the ~denote-rename-buffer-mode~
([[#h:3ca4db16-8f26-4d7d-b748-bac48ae32d69][Automatically rename Denote file buffers]]).

The value of this user option is a string that gets combined with the
~denote-buffer-name-prefix~ ([[#h:a3a1a2af-a0b8-420c-acb1-855a7d113e69][Set the prefix of all Denote buffers]]).
The following specifiers are placeholders for Denote file name
components ([[#h:4e9c7512-84dc-4dfb-9fa9-e15d51178e5d][The file-naming scheme]]):

#+vindex: denote-rename-buffer-backlinks-indicator
- The =%t= is the Denote =TITLE= in the front matter or the file name.
- The =%T= is the Denote =TITLE= in the file name.
- The =%i= is the Denote =IDENTIFIER= of the file.
- The =%I= is the identifier converted to =DAYNAME, DAYNUM MONTHNUM
  YEAR=.
- The =%d= is the same as =%i= (=DATE= mnemonic).
- The =%D= is a "do what I mean" which behaves the same as =%t= and if
  that returns nothing, it falls back to =%I=, then =%i=.
- The =%s= is the Denote =SIGNATURE= of the file.
- The =%k= is the Denote =KEYWORDS= of the file.
- The =%b= is an indicator of whether or not the file has backlinks
  pointing to it. The indicator string is defined in the user option
  ~denote-rename-buffer-backlinks-indicator~, alias
  ~denote-buffer-has-backlinks-string~.
- The =%%= is a literal percent sign.

In addition, the following flags are available for each of the specifiers:

- =0= :: Pad to the width, if given, with zeros instead of spaces.
- =-= :: Pad to the width, if given, on the right instead of the left.
- =<= :: Truncate to the width and precision, if given, on the left.
- =>= :: Truncate to the width and precision, if given, on the right.
- =^= :: Convert to upper case.
- =_= :: Convert to lower case.

When combined all together, the above are written thus:

: %<flags><width><precision>SPECIFIER-CHARACTER

Any other string it taken as-is.

Users who need yet more flexibility are best served by writing their
own function and assigning it to the ~denote-rename-buffer-function~.

* Use Org dynamic blocks
:PROPERTIES:
:CUSTOM_ID: h:8b542c50-dcc9-4bca-8037-a36599b22779
:END:

This section is about the external package ~denote-org~ (by
Protesilaos). The code of ~denote-org~ used to be available as part of
the main ~denote~ package, but we decided to keep each optional
extension as a separate package to make things easier to maintain and
to understand.

Denote can optionally integrate with Org mode's "dynamic blocks"
facility. This means that it can use special blocks that are evaluated
with =C-c C-x C-u= (~org-dblock-update~) to generate their contents.

Dynamic blocks are particularly useful for metanote entries that
reflect on the status of earlier notes ([[#h:6060a7e6-f179-4d42-a9de-a9968aaebecc][Writing metanotes]]). The
~denote-org~ package defines many of these Org dynamic blocks.

+ Package name (GNU ELPA): ~denote-org~
+ Official manual: <https://protesilaos.com/emacs/denote-org>
+ Git repository: <https://github.com/protesilaos/denote-org>
+ Backronym: Denote... Ordinarily Restricts Gyrations.

* Display filtered and sorted files with ~denote-sort-dired~ or ~denote-dired~
:PROPERTIES:
:CUSTOM_ID: h:9fe01e63-f34f-4479-8713-f162a5ca865e
:END:

The =denote.el= file contains functions which empower user or
developers to sort files by the given file name component ([[#h:4e9c7512-84dc-4dfb-9fa9-e15d51178e5d][The file-naming scheme]]).

#+findex: denote-sort-dired
#+findex: denote-dired
The command ~denote-sort-dired~ (alias ~denote-dired~) produces a
Dired file listing with a flat, filtered, and sorted set of files from
the ~denote-directory~ ([[#h:c958e087-1d23-4a25-afdd-db7bf5606b4c][Define a sorting function per component]]). It
does so by a series of prompts, which can be configured with the user
option ~denote-sort-dired-extra-prompts~ ([[#h:a34228cb-484f-48fe-9cbc-8e41f313127b][Configure what extra prompts ~denote-sort-dired~ issues]]).

Think of ~denote-sort-dired~ as the counterpart to the Unix ~find~
command. While ~denote-grep~ corresponds to the Unix ~grep~ ([[#h:e71c9d14-7e88-4386-91d0-9ad249947077][Use ~denote-grep~ to search inside files]]).

The out-of-the-box behaviour of ~denote-sort-dired~ is as follows:

1. It first asks for a regular expression with which to match Denote
   file names. Remember that due to Denote's efficient file-naming
   scheme, you usually do not need to write some complex regular
   expression. For example, something like =_journal= will match only
   files with a =journal= keyword.
2. Once the regular expression is provided, the command asks for a
   Denote file name component to sort files by. This is a symbol among
   =title=, =keywords=, =signature=, and =identifier= ([[#h:c958e087-1d23-4a25-afdd-db7bf5606b4c][Define a sorting function per component]]).
3. Finally, it asks a "yes or no" on whether to reverse the sort order.

The resulting listing is a regular Dired buffer, unlike that of
~dired-virtual-mode~ ([[#h:d35d8d41-f51b-4139-af8f-9c8cc508e35b][Use ~dired-virtual-mode~ for arbitrary file listings]]).

#+findex: denote-sort-files
The sorting mechanism can be used by other packages to achieve their
ends. As an example, the dynamic Org blocks that the ~denote-org~
package (by Protesilaos) defines also use this feature internally by
means of the non-interactive function ~denote-sort-files~.

** Configure what extra prompts ~denote-sort-dired~ issues
:PROPERTIES:
:CUSTOM_ID: h:a34228cb-484f-48fe-9cbc-8e41f313127b
:END:

#+vindex: denote-sort-dired-extra-prompts
By default, the ~denote-sort-dired~ command prompts for (i) a query to
match file names, (ii) a file name component to sort by, and (iii)
whether to reverse the sorting ([[#h:9fe01e63-f34f-4479-8713-f162a5ca865e][Display filtered and sorted files with denote-sort-dired]]).
Users can configure the latter two by modifying the user option
~denote-sort-dired-extra-prompts~.

The ~denote-sort-dired-extra-prompts~ accepts either a nil value or a
list of symbols among ~sort-by-component~, ~reverse-sort~, and
~exclude-regexp~. The order those symbols appear in the list is
significant, with the leftmost coming first.

These symbols correspond to the following:

- A choice to select the file name component to sort by.
- A yes or no prompt on whether to reverse the sorting.
- A string (or regular expression) of files to be excluded from the
  results.

#+vindex: denote-sort-dired-default-sort-component
#+vindex: denote-sort-dired-default-reverse-sort
In case of a nil value, those extra prompts will not happen, meaning
that ~denote-sort-dired~ will fall back to using whatever is defined
in the variables ~denote-sort-dired-default-sort-component~ and
~denote-sort-dired-default-reverse-sort~.

Here are some examples:

#+begin_src emacs-lisp
;; The default extra prompts...
(setq denote-sort-dired-extra-prompts '(sort-by-component reverse-sort))

;; When using `denote-sort-dired', ask whether to reverse the sort and
;; then which file name component to sort by.  These are always done
;; after the prompt to search for files matching a regexp.
(setq denote-sort-dired-extra-prompts '(reverse-sort sort-by-component))

;; Do not prompt for a reverse sort.  Just use the value of
;; `denote-sort-dired-default-reverse-sort' (which is nil out-of-the-box).
(setq denote-sort-dired-extra-prompts '(sort-by-component))

;; Do not issue any extra prompts.  Always sort by the `title' file
;; name component and never do a reverse sort.
(setq denote-sort-dired-extra-prompts nil)
(setq denote-sort-dired-default-sort-component 'title)
(setq denote-sort-dired-default-reverse-sort nil)
#+end_src

** Define a sorting function per component
:PROPERTIES:
:CUSTOM_ID: h:c958e087-1d23-4a25-afdd-db7bf5606b4c
:END:

When sorting by =title=, =keywords=, =signature=, =identifier=,
=random=, or =last-modified= with the ~denote-dired~ command (alias ~denote-sort-dired~),
Denote will internally apply a sorting function that is specific to
each component ([[#h:a34228cb-484f-48fe-9cbc-8e41f313127b][Configure what extra prompts ~denote-sort-dired~ issues]]).

With the exception of =random= and =last-modified=, the sorting of
file name components is subject to user configuration:

#+vindex: denote-sort-identifier-comparison-function
- ~denote-sort-identifier-comparison-function~ :: The function to sort
  by the file name identifier.

#+vindex: denote-sort-title-comparison-function
- ~denote-sort-title-comparison-function~ :: The function to sort by
  the file name title.

#+vindex: denote-sort-keywords-comparison-function
- ~denote-sort-keywords-comparison-function~ :: The function to sort
  by the file name keywords.

#+vindex: denote-sort-signature-comparison-function
- ~denote-sort-signature-comparison-function~ :: The function to sort
  by the file name signature.

By default, all these user options use the same comparison function,
namely ~string-collate-lessp~. Users who have specific needs for any
of those file name components can write their own sorting algorithms
([[#h:95345870-4ccd-484f-9adf-de4747ad5760][Sort signatures that include Luhmann-style sequences]]).

*** Sort signatures that include Luhmann-style sequences
:PROPERTIES:
:CUSTOM_ID: h:95345870-4ccd-484f-9adf-de4747ad5760
:END:

[ The ~denote-sequence~ package (by Protesilaos) covers this use-case
  and many others ([[#h:d5ca722d-e7fa-46fa-9a57-6363b1d4186f][Write sequence notes or folgezettel]]). It is the
  superior option for anyone interested in this functionality. We keep
  the code below for reference, as there may be users of it who need
  to revisit it. Though long-term, it is better to use ~denote-sequence~. ]

Niklas Luhmann would edit notes to form sequences of thoughts with
branching paths, such as =1.1=, =1.1a=, =1.2=, =1.2a=, =1.2b=, etc.
With the Denote file-naming scheme, we make the word separator in each
file name component use the same character as the entire field, so
words in a title have a dash between them and signatures have the
equals sign ([[#h:4e9c7512-84dc-4dfb-9fa9-e15d51178e5d][The file-naming scheme]]). Thus, our Luhmann-style
signature will be slightly different in their looks: ~1=1~, ~1=1a~,
~1=2~, ~1=2a~, ~1=2b~.

When using the ~denote-sort-dired~ command with default settings, our
signatures will not sort in an intuitive way. This is because they
combine numbers and letters, which require a different approach than
what the default sorting function is using ([[#h:c958e087-1d23-4a25-afdd-db7bf5606b4c][Define a sorting function per component]]).
In the following code block, we show a sorting algorithm that should
do the right thing while dealing with Luhmann-style signatures.

#+begin_src emacs-lisp
(defun my-denote--split-luhman-sig (signature)
  "Split numbers and letters in Luhmann-style SIGNATURE string."
  (replace-regexp-in-string
   "\\([a-zA-Z]+?\\)\\([0-9]\\)" "\\1=\\2"
   (replace-regexp-in-string
    "\\([0-9]+?\\)\\([a-zA-Z]\\)" "\\1=\\2"
    signature)))

(defun my-denote--pad-sig (signature)
  "Create a new signature with padded spaces for all components"
  (combine-and-quote-strings
   (mapcar
    (lambda (x)
      (string-pad x 5 32 t))
    (split-string (my-denote--split-luhman-sig signature) "=" t))
   "="))

(defun my-denote-sort-for-signatures (sig1 sig2)
  "Return non-nil if SIG1 is smaller that SIG2.
Perform the comparison with `string<'."
  (string< (my-denote--pad-sig sig1) (my-denote--pad-sig sig2)))

;; Change the sorting function only when we sort by signature.
(setq denote-sort-signature-comparison-function #'my-denote-sort-for-signatures)
#+end_src

* Use ~denote-grep~ to search inside files
:PROPERTIES:
:CUSTOM_ID: h:e71c9d14-7e88-4386-91d0-9ad249947077
:END:

#+findex: denote-grep
The command ~denote-grep~ searches for the given query across all
readable files in the ~denote-directory~. It puts the collected
results in an Xref buffer (just like with our backlinks and query
links functionality). In this buffer, users can do =M-x describe-mode=
(=C-h m= with default key bindings) to learn about all the actions
they can perform and the keys they are bound to ([[#h:435592bc-e896-429f-a599-9f1bcd5ab9b8][Interact with the links buffer]]).

Think of ~denote-grep~ as the counterpart to the Unix ~grep~ command.
While ~denote-sort-dired~ corresponds to the Unix ~find~ ([[#h:9fe01e63-f34f-4479-8713-f162a5ca865e][Display filtered and sorted files with ~denote-sort-dired~]]).

#+findex: denote-grep-marked-dired-files
The command ~denote-grep-marked-dired-files~ is like ~denote-grep~ but
operates on the files that are marked in a Dired buffer.

#+findex: denote-grep-files-referenced-in-region
The command ~denote-grep-files-referenced-in-region~ is like
~denote-grep~ for any files referenced within the boundaries of the
marked region. Files are referenced by their identifier. This includes
links with just the identifier (as described in ~denote-link~ and
related ([[#h:5e5e3370-12ab-454f-ba09-88ff44214324][Add a single direct link using a file name prompt]])), links
written by an Org dynamic block (see the ~denote-org~ package ([[#h:8b542c50-dcc9-4bca-8037-a36599b22779][Use Org dynamic blocks]])),
or even file listings such as those of ~dired~ and the command-line
~ls~ program.

#+vindex: denote-grep-display-buffer-action
The user option ~denote-grep-display-buffer-action~ controls where the
buffer with the search results is displayed at. By default, they appear in
the same window where the command ~denote-grep~ is called from.

* Interact with the links buffer
:PROPERTIES:
:CUSTOM_ID: h:435592bc-e896-429f-a599-9f1bcd5ab9b8
:END:

Denote commands, such as ~denote-grep~, ~denote-backlinks~, and
~denote-query-contents-link~, produce an Xref buffer with search
results ([[#h:893eec49-d7be-4603-bcff-fcc247244011][Speed up backlinks' or query links' buffer creation?]]).
Matching lines are grouped by the file name they belong to.

- [[#h:e71c9d14-7e88-4386-91d0-9ad249947077][Use ~denote-grep~ to search inside files]].
- [[#h:c73f1f68-e214-49d5-b369-e694f6a5d708][The backlinks' buffer]].
- [[#h:d9a84289-2f73-4ef9-b4f0-9a0aa3e9bf0d][Add a query link]].

#+findex: denote-query-mode
#+vindex: denote-query-mode-map
This buffer uses the major mode ~denote-query-mode~. It binds commands
to keys in the ~denote-query-mode-map~. Those allow users to filter
the output of the last search. Here, "last search" refers to the list
of files that were returned by whichever command produced the buffer
(e.g. the last ~denote-grep~).

#+findex: denote-query-focus-last-search
- ~denote-query-focus-last-search~ :: Perform a search in the contents
  of files that were matched by the last search.

#+findex: denote-query-exclude-files
- ~denote-query-exclude-files~ :: Exclude files from the last search
  whose name matches the given input.

#+findex: denote-query-only-include-files
- ~denote-query-only-include-files~ :: Only keep files from the last
  search whose name matches the given input.

#+findex: denote-query-exclude-files-with-keywords
- ~denote-query-exclude-files-with-keywords~ :: Exclude files from the
  last search whose name includes the given keywords.

#+findex: denote-query-only-include-files-with-keywords
- ~denote-query-only-include-files-with-keywords~ :: Only keep files
  from the last search whose name includes the given keywords.

#+findex: denote-query-clear-all-filters
- ~denote-query-clear-all-filters~ :: Clear all the applied filters.

#+findex: denote-query-sort-last-search
- ~denote-query-sort-last-search~ :: Change the sorting of files from
  the last search. The user option ~denote-query-sorting~ controlls
  the default sort ([[#h:ec3d009a-518b-439f-a3e5-38342b1c13fe][Control the default sort of a query buffer]]).

Remember that these are easy to use even without knowledge of regular
expressions, thanks to the efficiency of the Denote file-naming scheme
([[#h:1a953736-86c2-420b-b566-fb22c97df197][Features of the file-naming scheme for searching or filtering]]). For
instance, to exclude notes with the keyword =philosophy= from current
search buffer, use ~denote-query-exclude-files~ and then type
=_philosophy= as your input.

In addition to those filtering options, the ~denote-query-mode~ also
allows provides an outline mechanism to hide or show the matches as
these are grouped per file. There also are some of the default actions
provided by the Xref infrastructure. Users can do =M-x describe-mode=
(=C-h m= with default key bindings) to learn about all the actions
they can perform.

** Control the default sort of a query buffer
:PROPERTIES:
:CUSTOM_ID: h:ec3d009a-518b-439f-a3e5-38342b1c13fe
:END:

#+vindex: denote-query-sorting
The user option ~denote-query-sorting~ controls the order of matching
files in a query buffer (buffers that use the ~denote-query-mode~. The
applies to the buffer that is produced by query links for file
contents, backlinks, and the ~denote-grep~ command:

- [[#h:d9a84289-2f73-4ef9-b4f0-9a0aa3e9bf0d][Add a query link]].
- [[#h:c73f1f68-e214-49d5-b369-e694f6a5d708][The backlinks' buffer]].
- [[#h:e71c9d14-7e88-4386-91d0-9ad249947077][Use ~denote-grep~ to search inside files]].

By default (a ~nil~ value), no sorting of matching files is performed.
Files are displayed in the order they are returned by the search
program (which often, but not always, means they are sorted by file
name).

#+vindex: denote-sort-components
The ~denote-query-sorting~ can be set to a symbol among those listed
in the value of the variable ~denote-sort-components~ to sort by the
given file name component ([[#h:4e9c7512-84dc-4dfb-9fa9-e15d51178e5d][The file-naming scheme]]). The symbol
=random= produces a random order each time, while =last-modified=
relies on the file system to sort by the modification time.

The ~denote-query-sorting~ can also be set to the symbol of a
function. In that case, the given function is used to perform the
sorting. This is for advanced users, who may refer to the
documentation of the ~denote-sort-files~ for the technicalities.

Whatever the value of ~denote-query-sorting~, users may change the
sorting of query buffers on demand by calling the command
~denote-query-sort-last-search~ ([[#h:435592bc-e896-429f-a599-9f1bcd5ab9b8][Interact with the links buffer]]).

* Minibuffer histories
:PROPERTIES:
:CUSTOM_ID: h:82dc1203-d689-44b2-9a6c-b37776209651
:END:

Denote has a dedicated minibuffer history for each one of its prompts.
This practically means that using =M-p= (~previous-history-element~) and
=M-n= (~next-history-element~) will only cycle through the relevant
record of inputs, such as your latest titles in the =TITLE= prompt, and
keywords in the =KEYWORDS= prompt.

The built-in =savehist= library saves minibuffer histories.  Sample
configuration:

#+begin_src emacs-lisp
(require 'savehist)
(setq savehist-file (locate-user-emacs-file "savehist"))
(setq history-length 500)
(setq history-delete-duplicates t)
(setq savehist-save-minibuffer-history t)
(add-hook 'after-init-hook #'savehist-mode)
#+end_src

* Packages that build on Denote
:PROPERTIES:
:CUSTOM_ID: h:08b14682-e73f-4b11-b2e2-be3b788c8572
:END:

This is a list of packages that extend Denote. If you are a package
author, please let us know about your work and we will include it
here (either use the Git repositories or email Protesilaos directly).

** Use the ~consult-denote~ package for enhanced minibuffer interactions
:PROPERTIES:
:CUSTOM_ID: h:113a13e1-35da-46f1-9414-81e9be2facc1
:END:

The ~consult-denote~ package by me (Protesilaos) integrates Denote
with Daniel Mendler's ~consult~ package: <https://github.com/protesilaos/consult-denote>.

The idea is to preserve the familiar patterns of interaction with the
various Denote commands but add to them an extra layer of
functionality, such as the preview mechanism that Consult provides
(e.g. preview the file you are about to link to).

Additionally, ~consult-denote~ defines new "sources" for the
~consult-buffer~ command. This command provides a single point of
entry for buffers, recently opened files, and bookmarks. With
~consult-denote~, it has a dedicated place for Denote-specific
buffers, silos, and more (all of which are configurable).

Unlike the ~consult-notes~ package by Colin McLear, ~consult-denote~
uses the same presentation of data in the minibuffer to stay in sync
with Denote and make its feature set entirely optional ([[#h:8907f4bc-992a-45bc-a60e-267ed1ce9c2d][Use the ~consult-notes~ package]]).
It also only works with Denote.

** Use the ~denote-sequence~ package to write sequence notes or "folgezettel"
:PROPERTIES:
:CUSTOM_ID: h:d5ca722d-e7fa-46fa-9a57-6363b1d4186f
:ALT_TITLE: Sequence notes
:END:

This section is about the external package ~denote-sequence~ (by
Protesilaos). The original idea was to include the code as part of the
~denote~ package, but we decided to keep each optional extension as a
separate package to make things easier to maintain and to understand.

Denote defines an optional file name component called the =SIGNATURE=
([[#h:4e9c7512-84dc-4dfb-9fa9-e15d51178e5d][The file-naming scheme]]). This is a free-form field that users can
fill in with whatever text they want, such as to have a video split up
into =part1= and =part2=, or to set some kind of priority like =a= and
=b=, or even to have a special tag that stands out from the rest of
the keywords.

A more specialised use-case of the =SIGNATURE= is to define a
hierarchical relationship between notes, such that the thoughts they
expound on form sequences. For example, an article about the Labrador
Retriever dog breed is a continuation of a thought process that
extends something about dog breeds in general which, in turn, is a
topic that belongs to the wider theme of dogs.

The ~denote-sequence~ package has a manual that explains these
concepts and relevant commands in further detail:

+ Package name (GNU ELPA): ~denote-sequence~
+ Official manual: <https://protesilaos.com/emacs/denote-sequence>
+ Git repository: <https://github.com/protesilaos/denote-sequence>
+ Backronym: Denote... Sequences Efficiently Queue Unsorted Entries
  Notwithstanding Curation Efforts.

** Use the ~denote-markdown~ package to better integrate Markdown with Denote
:PROPERTIES:
:CUSTOM_ID: h:79b614e7-d7a3-4953-b776-216e6e1ede77
:END:

The ~denote-markdown~ package (by Protesilaos) provides some
convenience functions to better integrate Markdown with Denote. This
is mostly about converting links from one type to another so that they
can work in different applications (because Markdown does not have a
standardised way to define custom link types).

The code of ~denote-markdown~ used to be bundled up with the ~denote~
package before version =4.0.0= of the latter and was available in the
file =denote-md-extras.el=. Users of the old code will need to adapt
their setup to use the ~denote-markdown~ package. This can be done by
replacing all instances of =denote-md-extras= with =denote-markdown=
across their configuration.

+ Package name (GNU ELPA): ~denote-markdown~
+ Official manual: <https://protesilaos.com/emacs/denote-markdown>
+ Git repository: <https://github.com/protesilaos/denote-markdown>
+ Backronyms: Denote... Markdown's Ambitious Reimplimentations
  Knowingly Dilute Obvious Widespread Norms; Denote... Markup
  Agnosticism Requires Knowhow to Do Only What's Necessary.

** Use the ~denote-journal~ package which was formerly =denote-journal-extras.el=
:PROPERTIES:
:CUSTOM_ID: h:4a6d92dd-19eb-4fcc-a7b5-05ce04da3a92
:END:

The ~denote-journal~ package (by Protesilaos) makes it easier to use
Denote for journaling. While it is possible to use the generic
~denote~ command (and related) to maintain a journal, this package
defines extra functionality to streamline the journaling workflow.

The code of ~denote-journal~ used to be bundled up with the ~denote~
package before version =4.0.0= of the latter and was available in the
file =denote-journal-extras.el=. Users of the old code will need to
adapt their setup to use the ~denote-journal~ package. This can be
done by replacing all instances of =denote-journal-extras= with
=denote-journal= across their configuration.

+ Package name (GNU ELPA): ~denote-journal~
+ Official manual: <https://protesilaos.com/emacs/denote-journal>
+ Git repository: <https://github.com/protesilaos/denote-journal>
+ Backronym: Denote... Journaling Obviously Utilises Reasonableness
  Notwithstanding Affectionate Longing.

** Use the ~denote-silo~ package which formerly was =denote-silo-extras.el=
:PROPERTIES:
:CUSTOM_ID: h:e43baf95-f201-4fec-8620-c0eb5eaa1c85
:END:

The ~denote-silo~ package (by Protesilaos) provides convenience
functions for working with silos ([[#h:15719799-a5ff-4e9a-9f10-4ca03ef8f6c5][Maintain separate directory silos for notes]]).

The code of ~denote-silo~ used to be bundled up with the ~denote~
package before version =4.0.0= of the latter and was available in the
file =denote-silo-extras.el=. Users of the old code will need to adapt
their setup to use the ~denote-silo~ package. This can be done by
replacing all instances of =denote-silo-extras= with =denote-silo=
across their configuration.

+ Package name (GNU ELPA): ~denote-silo~
+ Official manual: <https://protesilaos.com/emacs/denote-silo>
+ Git repository: <https://github.com/protesilaos/denote-silo>
+ Backronym: Denote... Silos Insulate Localised Objects.

** Use the ~denote-search~ package as a search interface
:PROPERTIES:
:CUSTOM_ID: h:c905b733-e959-4aa4-8f2c-0ed9eba459df
:END:

[ As part of version =4.0.0=, Denote comes with the ~denote-grep~
  command and related functionality ([[#h:e71c9d14-7e88-4386-91d0-9ad249947077][Use ~denote-grep~ to search inside files]]).
  The core of this feature set was written by Lucas Quintana. ]

The ~denote-search~ package by Lucas Quintana provides a search
utility for Denote: <https://github.com/lmq-10/denote-search>.

It allows you to search for a regular expression in the content of
your notes. Its main advantages over other similar tools are the
possibility of filtering the results by file name and doing further
searches in the files matched previously. This allows for advanced
usage (think about finding a note with two or three specific words in
different lines and with a specific keyword). More features are
described in its comprehensive manual. ~denote-search~ builds upon
standard Emacs libraries, namely Xref, and so it doesn't have external
dependencies other than Denote itself.

** Use the ~denote-explore~ package to explore your notes
:PROPERTIES:
:CUSTOM_ID: h:110ae3a4-5fc6-45da-b9bb-0e294bd12981
:END:

Peter Prevos has developed the ~denote-explore~ package which provides
four groups of Emacs commands to explore your Denote files:

- Summary statistics :: Count notes, attachments and keywords.
- Random walks :: Generate new ideas using serendipity.
- Janitor :: Manage your denote collection.
- Visualisations :: Visualise your Denote network.

The package's documentation covers the details:
<https://lucidmanager.org/productivity/denote-explore/>.

** Use the ~citar-denote~ package for bibliography notes
:PROPERTIES:
:CUSTOM_ID: h:226d66e4-b7de-4617-87e2-a7f2d6f007dd
:END:

Peter Prevos has produced the ~citar-denote~ package which makes it
possible to write notes on BibTeX entries with the help of the ~citar~
package.  These notes have the citation's unique key associated with
them in the file's front matter.  They also get a configurable keyword
in their file name, making it easy to find them in Dired and/or
retrieve them with the various Denote methods.

With ~citar-denote~, the user leverages standard minibuffer completion
mechanisms (e.g. with the help of the ~vertico~ and ~embark~ packages)
to manage bibliographic notes and access those notes with ease.  The
package's documentation covers the details: <https://lucidmanager.org/productivity/bibliographic-notes-in-emacs-with-citar-denote/>.

** Use the ~consult-notes~ package
:PROPERTIES:
:CUSTOM_ID: h:8907f4bc-992a-45bc-a60e-267ed1ce9c2d
:END:

[ Also check the ~consult-denote~ package by me (Protesilaos):
  [[#h:113a13e1-35da-46f1-9414-81e9be2facc1][Use the ~consult-denote~ package for enhanced minibuffer interactions]]. ]

If you are using Daniel Mendler's ~consult~ (which is a brilliant
package), you will most probably like its ~consult-notes~ extension,
developed by Colin McLear.  It uses the familiar mechanisms of Consult
to preview the currently selected entry and to filter searches via a
prefix key.  For example:

#+begin_src emacs-lisp
(setq consult-notes-file-dir-sources
      `(("Denote Notes"  ?d ,(denote-directory))
        ("Books"  ?b "~/Documents/books/")))
#+end_src

With the above, =M-x consult-notes= will list the files in those two
directories.  If you type =d= and space, it narrows the list to just
the notes, while =b= does the same for books.

The other approach is to enable the ~consult-notes-denote-mode~.  It
takes care to add the ~denote-directory~ to the sources that
~consult-notes~ reads from.  Denote notes are then filtered by the =d=
prefix followed by a space.

The minor mode has the extra feature of reformatting the title of
notes shown in the minibuffer.  It isolates the =TITLE= component of
each note and shows it without hyphens, while presenting keywords in
their own column.  The user option ~consult-notes-denote-display-id~
can be set to ~nil~ to hide the identifier.  Depending on how one
searches through their notes, this refashioned presentation may be the
best option ([[#h:1a953736-86c2-420b-b566-fb22c97df197][Features of the file-naming scheme for searching or filtering]]).

** Use the ~denote-menu~ package
:PROPERTIES:
:CUSTOM_ID: h:472db709-27de-4a1f-a171-c3fe0a7a9be8
:END:

Denote's file-naming scheme is designed to be efficient and to provide
valueable meta information about the file.  The cost, however, is that
it is terse and harder to read, depending on how the user chooses to
filter and process their notes.

To this end, [[https://github.com/namilus/denote-menu][the ~denote-menu~ package by Mohamed Suliman]] provides the
convenience of a nice tabular interface for all notes.  ~denote-menu~
removes the delimiters that are found in Denote file names and
presents the information in a human-readable format.  Furthermore, the
package provides commands to interact with the list of notes, such as
to filter them and to transition from the tabular list to Dired.  Its
documentation expands on the technicalities.

** Use the ~denote-zettel-interface~ package
:PROPERTIES:
:CUSTOM_ID: h:b57f73fc-ac4d-4df2-bd7a-8d47cb202647
:END:

The [[https://github.com/krisbalintona/denote-zettel-interface][~denote-zettel-interface~ package by Kristoffer Balintona]] is
designed for those who want to use Denote while adhering to a strict
Zettelkasten methodology of sequence notes (Folgezettel). This method
leverages the optional =SIGNATURE= file name component of Denote ([[#h:4e9c7512-84dc-4dfb-9fa9-e15d51178e5d][The file-naming scheme]]).
The package provides a point of entry to one's note by visualising
them in a tabulated (grid) interface. Files are sorted by their
Folgezettel index. Users can then use a number of commands to filter
their files, navigate around, and the like.

Note that the package is in early development as of this writing
(2024-12-03 10:18 +0200).

* Extending Denote
:PROPERTIES:
:CUSTOM_ID: h:8ed2bb6f-b5be-4711-82e9-8bee5bb06ece
:END:

Denote is a tool with a narrow scope: create notes and link between
them, based on the aforementioned file-naming scheme. For other common
operations the user is advised to rely on standard Emacs facilities or
specialised third-party packages ([[#h:08b14682-e73f-4b11-b2e2-be3b788c8572][Packages that build on Denote]]). This
section covers the details.

** Access the data of the latest note
:PROPERTIES:
:CUSTOM_ID: h:a947908e-1847-4471-ba07-377ee2f4b36c
:END:

#+vindex: denote-current-data
The variable ~denote-current-data~ is updated each time a new note is
created as well as after a rename operation.

This is an alist where each ~car~ is one among ~title~, ~keywords~,
~signature~, ~directory~, ~date~, ~id~, ~file-type~, ~template~. The
value each of them contains is the unprocessed input (e.g. the title
before it is sluggified).

Users who need to access this data as part of their custom code can
rely on the hooks ~denote-after-new-note-hook~ and
~denote-after-rename-file-hook~.

** Create a new note in any directory
:PROPERTIES:
:CUSTOM_ID: h:c9d7c157-85a6-4bb7-bd21-d00bccf5e799
:END:

The commands that create new files are designed to write to the
~denote-directory~. The idea is that the linking mechanism can find
any file by its identifier if it is in the ~denote-directory~
(searching the entire file system would be cumbersome).

However, these are cases where the user needs to create a new note in
an arbitrary directory. The following command can do this. Put the
code in your configuration file and evaluate it. Then call the command
by its name with =M-x=.

#+begin_src emacs-lisp
(defun my-denote-create-note-in-any-directory ()
  "Create new Denote note in any directory.
Prompt for the directory using minibuffer completion."
  (declare (interactive-only t))
  (interactive)
  (let ((denote-directory (read-directory-name "New note in: " nil nil :must-match)))
    (call-interactively 'denote)))
#+end_src

** Find empty notes and put them in a Dired buffer
:PROPERTIES:
:CUSTOM_ID: h:bbc7a769-19e8-4598-a2b7-06e1d673ae80
:END:

[ This feature is based on the command ~denote-sort-dired~ ([[#h:9fe01e63-f34f-4479-8713-f162a5ca865e][Sort files by component]]). ]

Users may have a workflow where they use the commands
~denote-link-or-create~ or ~denote-link-after-creating~ (and related)
to produce new notes that they plan to elaborate on later ([[#h:b6056e6b-93df-4e6b-a778-eebd105bac46][Link to an existing note or create a new one]]).

To help users find those empty notes, we document the following
commands:

- ~my-denote-sort-dired-empty-files~
- ~my-denote-sort-dired-without-empty-files~
- ~my-denote-sort-dired-all-empty-files~
- ~my-denote-sort-dired-without-all-empty-files~

#+begin_src emacs-lisp
(defun my-denote--note-has-no-contents-p (file)
  "Return non-nil if FILE is an empty note.
This means that FILE conforms with `denote-file-is-note-p' and either
has no contents or has only the front matter."
  (and (denote-file-is-note-p file)
       (or (denote--file-with-temp-buffer file
             (re-search-forward "^$" nil t)
             (if (re-search-forward "[^\s\t\n\r]+" nil t)
                 nil
               t))
           ;; This must come later because here we consider a file
           ;; "empty" even if it only has front matter.
           (denote--file-empty-p file))))

(defun my-denote-sort-dired-empty-files (files-matching-regexp sort-by-component reverse exclude-regexp)
  "Like `denote-sort-dired' but only cover empty files.
Empty files are those that satisfy `my-denote--note-has-no-contents-p'."
  (interactive (append (list (denote-files-matching-regexp-prompt)) (denote-sort-dired--prompts)))
  (pcase-let* ((`(,component . ,reverse-sort) (denote-sort-dired--get-sort-parameters sort-by-component reverse))
               (relative-p (denote-has-single-denote-directory-p))
               (files-fn `(lambda ()
                           (let* ((files (denote-sort-get-directory-files ,files-matching-regexp ',component ,reverse-sort))
                                  (empty-files (seq-filter #'my-denote--note-has-no-contents-p files)))
                             (if relative-p
                                 (mapcar #'file-relative-name empty-files)
                               empty-files)))))
    (if-let* ((directory (if relative-p ; see comment in `denote-file-prompt'
                             (car (denote-directories))
                           (denote-directories-get-common-root)))
              (files (funcall files-fn))
              (dired-name (format-message files-matching-regexp))
              (buffer-name (funcall denote-sort-dired-buffer-name-function (format "%s (EMPTY)" files-matching-regexp) sort-by-component reverse-sort exclude-regexp)))
        (denote-sort-dired--prepare-buffer directory files-fn dired-name buffer-name)
      (message "No matching files for: %s" files-matching-regexp))))

(defun my-denote-sort-dired-without-empty-files (files-matching-regexp sort-by-component reverse exclude-regexp)
  "Like `denote-sort-dired' but omit empty files.
Empty files are those that satisfy `my-denote--note-has-no-contents-p'."
  (interactive (append (list (denote-files-matching-regexp-prompt)) (denote-sort-dired--prompts)))
  (pcase-let* ((`(,component . ,reverse-sort) (denote-sort-dired--get-sort-parameters sort-by-component reverse))
               (relative-p (denote-has-single-denote-directory-p))
               (files-fn `(lambda ()
                           (let* ((files (denote-sort-get-directory-files ,files-matching-regexp ',component ,reverse-sort))
                                  (empty-files (seq-remove #'my-denote--note-has-no-contents-p files)))
                             (if relative-p
                                 (mapcar #'file-relative-name empty-files)
                               empty-files)))))
    (if-let* ((directory (if relative-p ; see comment in `denote-file-prompt'
                             (car (denote-directories))
                           (denote-directories-get-common-root)))
              (files (funcall files-fn))
              (dired-name (format-message files-matching-regexp))
              (buffer-name (funcall denote-sort-dired-buffer-name-function (format "%s (OMIT EMPTY)" files-matching-regexp) sort-by-component reverse-sort exclude-regexp)))
        (denote-sort-dired--prepare-buffer directory files-fn dired-name buffer-name)
      (message "No matching files for: %s" files-matching-regexp))))

(defun my-denote-sort-dired-all-empty-files ()
  "List all empty files in a Dired buffer.
This is the same as calling `my-denote-sort-dired' with a
FILES-MATCHING-REGEXP of \".*\"."
  (declare (interactive-only t))
  (interactive)
  (pcase-let ((`(,sort-by ,reverse ,exclude-rx) (denote-sort-dired--prompts)))
    (my-denote-sort-dired-empty-files ".*" sort-by reverse exclude-rx)))

(defun my-denote-sort-dired-without-all-empty-files ()
  "List all empty files in a Dired buffer.
This is the same as calling `my-denote-sort-dired' with a
FILES-MATCHING-REGEXP of \".*\"."
  (declare (interactive-only t))
  (interactive)
  (pcase-let ((`(,sort-by ,reverse ,exclude-rx) (denote-sort-dired--prompts)))
    (my-denote-sort-dired-without-empty-files ".*" sort-by reverse exclude-rx)))
#+end_src

[ In the above snippet, I am purposefully duplicating code to make it
  easier for users to pick the ones they need. ]

** Automatically rename the note after saving it
:PROPERTIES:
:CUSTOM_ID: h:c7d4dd3a-38bb-4f1c-a36e-989ec0bc79a6
:END:

While experimenting with Denote, users may need to try different
workflows to figure out what works for them. Those might involve
changing keywords and specifying titles in a particular way. The
following sample can be used:

#+begin_src emacs-lisp
(defun my-denote-always-rename-on-save-based-on-front-matter ()
  "Rename the current Denote file, if needed, upon saving the file.
Rename the file based on its front matter, checking for changes in the
title or keywords fields.

Add this function to the `after-save-hook'."
  (let ((denote-rename-confirmations nil)
        (denote-save-buffers t)) ; to save again post-rename
    (when (and buffer-file-name (denote-file-is-note-p buffer-file-name))
      (ignore-errors (denote-rename-file-using-front-matter buffer-file-name))
      (message "Buffer saved; Denote file renamed"))))

(add-hook 'after-save-hook #'my-denote-always-rename-on-save-based-on-front-matter)
#+end_src

** Narrow the list of files in Dired
:PROPERTIES:
:CUSTOM_ID: h:ea173a01-69ef-4574-89a7-6e60ede02f13
:END:

Emacs' standard file manager (or directory editor) can read a regular
expression to mark the matching files.  This is the command
~dired-mark-files-regexp~, which is bound to =% m= by default.  For
example, =% m _denote= will match all files that have the =denote=
keyword ([[#h:1a953736-86c2-420b-b566-fb22c97df197][Features of the file-naming scheme for searching or filtering]]).

Once the files are matched, the user has two options: (i) narrow the
list to the matching items or (ii) exclude the matching items from the
list.

For the former, we want to toggle the marks by typing =t= (calls the
command ~dired-toggle-marks~ by default) and then hit the letter =k=
(for ~dired-do-kill-lines~).  The remaining files are those that match
the regexp that was provided earlier.

For the latter approach of filtering out the matching items, simply
involves the use of the =k= command (~dired-do-kill-lines~) to omit the
marked files from the list.

These sequences can be combined to incrementally narrow the list.  Note
that ~dired-do-kill-lines~ does not delete files: it simply hides them
from the current view.

Revert to the original listing with =g= (~revert-buffer~).

For a convenient wrapper, consider this example:

#+begin_src emacs-lisp
(defvar prot-dired--limit-hist '()
  "Minibuffer history for `prot-dired-limit-regexp'.")

;;;###autoload
(defun prot-dired-limit-regexp (regexp omit)
  "Limit Dired to keep files matching REGEXP.

With optional OMIT argument as a prefix (\\[universal-argument]),
exclude files matching REGEXP.

Restore the buffer with \\<dired-mode-map>`\\[revert-buffer]'."
  (interactive
   (list
    (read-regexp
     (concat "Files "
             (when current-prefix-arg
               (propertize "NOT " 'face 'warning))
             "matching PATTERN: ")
     nil 'prot-dired--limit-hist)
    current-prefix-arg))
  (dired-mark-files-regexp regexp)
  (unless omit (dired-toggle-marks))
  (dired-do-kill-lines))
#+end_src

** Use ~dired-virtual-mode~ for arbitrary file listings
:PROPERTIES:
:CUSTOM_ID: h:d35d8d41-f51b-4139-af8f-9c8cc508e35b
:END:

Emacs' Dired is a powerful file manager that builds its functionality
on top of the Unix =ls= command.  As noted elsewhere in this manual,
the user can update the =ls= flags that Dired uses to display its
contents ([[#h:a7fd5e0a-78f7-434e-aa2e-e150479c16e2][I want to sort by last modified, why won't Denote let me?]]).

What Dired cannot do is parse the output of a result that is produced
by piped commands, such as =ls -l | sort -t _ -k2=.  This specific
example targets the second underscore-separated field of the file
name, per our conventions ([[#h:4e9c7512-84dc-4dfb-9fa9-e15d51178e5d][The file-naming scheme]]).  Conceretely, it
matches the "alpha" as the sorting key in something like this:

#+begin_src emacs-lisp
20220929T200432--testing-file-one__alpha.txt
#+end_src

Consider then, how Dired will sort those files by their identifier:

#+begin_src emacs-lisp
20220929T200432--testing-file-one__alpha.txt
20220929T200532--testing-file-two__beta.txt
20220929T200632--testing-file-three__alpha.txt
20220929T200732--testing-file-four__beta.txt
#+end_src

Whereas on the command line, we can get the following:

#+begin_example
$ ls | sort -t _ -k 2
20220929T200432--testing-file-one__alpha.txt
20220929T200632--testing-file-three__alpha.txt
20220929T200532--testing-file-two__beta.txt
20220929T200732--testing-file-four__beta.txt
#+end_example

This is where ~dired-virtual-mode~ shows its utility.  If we tweak our
command-line invocation to include =ls -l=, this mode can behave like
Dired on the listed files.  (We omit the output of the =-l= flag from
this tutorial, as it is too verbose.)

What we now need is to capture the output of =ls -l | sort -t _ -k 2=
in an Emacs buffer and then enable ~dired-virtual-mode~.  To do that,
we can rely on either =M-x shell= or =M-x eshell= and then manually
copy the relevant contents.

For the user's convenience, I share what I have for Eshell to quickly
capture the last command's output in a dedicated buffer:

#+begin_src emacs-lisp
(defcustom prot-eshell-output-buffer "*Exported Eshell output*"
  "Name of buffer with the last output of Eshell command.
Used by `prot-eshell-export'."
  :type 'string
  :group 'prot-eshell)

(defcustom prot-eshell-output-delimiter "* * *"
  "Delimiter for successive `prot-eshell-export' outputs.
This is formatted internally to have newline characters before
and after it."
  :type 'string
  :group 'prot-eshell)

(defun prot-eshell--command-prompt-output ()
  "Capture last command prompt and its output."
  (let ((beg (save-excursion
               (goto-char (eshell-beginning-of-input))
               (goto-char (point-at-bol)))))
    (when (derived-mode-p 'eshell-mode)
      (buffer-substring-no-properties beg (eshell-end-of-output)))))

;;;###autoload
(defun prot-eshell-export ()
  "Produce a buffer with output of the last Eshell command.
If `prot-eshell-output-buffer' does not exist, create it.  Else
append to it, while separating multiple outputs with
`prot-eshell-output-delimiter'."
  (interactive)
  (let ((eshell-output (prot-eshell--command-prompt-output)))
    (with-current-buffer (get-buffer-create prot-eshell-output-buffer)
      (let ((inhibit-read-only t))
        (goto-char (point-max))
        (unless (eq (point-min) (point-max))
          (insert (format "\n%s\n\n" prot-eshell-output-delimiter)))
        (goto-char (point-at-bol))
        (insert eshell-output)
        (switch-to-buffer-other-window (current-buffer))))))
#+end_src

Bind ~prot-eshell-export~ to a key in the ~eshell-mode-map~ and give
it a try (I use =C-c C-e=).  In the produced buffer, activate the
~dired-virtual-mode~.

** Use Embark to collect minibuffer candidates
:PROPERTIES:
:CUSTOM_ID: h:edf9b651-86eb-4d5f-bade-3c9e270082f0
:END:

=embark= is a remarkable package that lets you perform relevant,
context-dependent actions using a prefix key (simplifying in the
interest of brevity).

For our purposes, Embark can be used to produce a Dired listing
directly from the minibuffer.  Suppose the current note has links to
three other notes.  You might use the ~denote-find-link~ command to
pick one via the minibuffer.  But why not turn those three links into
their own Dired listing?  While in the minibuffer, invoke ~embark-act~
which you may have already bound to =C-.= and then follow it up with
=E= (for the ~embark-export~ command).

This pattern can be repeated with any list of candidates, meaning that
you can narrow the list by providing some input before eventually
exporting the results with Embark.

Overall, this is very powerful and you might prefer it over doing the
same thing directly in Dired, since you also benefit from all the power
of the minibuffer ([[#h:ea173a01-69ef-4574-89a7-6e60ede02f13][Narrow the list of files in Dired]]).

** Search file contents
:PROPERTIES:
:CUSTOM_ID: h:76198fab-d6d2-4c67-9ccb-7a08cc883952
:END:

[ This is not needed given that we provide the ~denote-grep~ command
  ([[#h:e71c9d14-7e88-4386-91d0-9ad249947077][Use ~denote-grep~ to search inside files]]). ]

Emacs provides built-in commands which are wrappers of standard Unix
tools: =M-x grep= lets the user input the flags of a ~grep~ call and
pass a regular expression to the =-e= flag.

The author of Denote uses this thin wrapper instead:

#+begin_src emacs-lisp
(defvar prot-search--grep-hist '()
  "Input history of grep searches.")

;;;###autoload
(defun prot-search-grep (regexp &optional recursive)
  "Run grep for REGEXP.

Search in the current directory using `lgrep'.  With optional
prefix argument (\\[universal-argument]) for RECURSIVE, run a
search starting from the current directory with `rgrep'."
  (interactive
   (list
    (read-from-minibuffer (concat (if current-prefix-arg
                                      (propertize "Recursive" 'face 'warning)
                                    "Local")
                                  " grep for PATTERN: ")
                          nil nil nil 'prot-search--grep-hist)
    current-prefix-arg))
  (unless grep-command
    (grep-compute-defaults))
  (if recursive
      (rgrep regexp "*" default-directory)
    (lgrep regexp "*" default-directory)))
#+end_src

Rather than maintain custom code, consider using the excellent =consult=
package: it provides commands such as ~consult-grep~ and ~consult-find~
which provide live results and are generally easier to use than the
built-in commands.

** Bookmark the directory with the notes
:PROPERTIES:
:CUSTOM_ID: h:1bba4c1e-6812-4749-948f-57df4fd49b36
:END:

Part of the reason Denote does not reinvent existing functionality is to
encourage you to learn more about Emacs.  You do not need a bespoke
"jump to my notes" directory because such commands do not scale well.
Will you have a "jump to my downloads" then another for multimedia and
so on?  No.

Emacs has a built-in framework for recording persistent markers to
locations.  Visit the ~denote-directory~ (or any dir/file for that
matter) and invoke the ~bookmark-set~ command (bound to =C-x r m= by
default).  It lets you create a bookmark.

The list of bookmarks can be reviewed with the ~bookmark-bmenu-list~
command (bound to =C-x r l= by default).  A minibuffer interface is
available with ~bookmark-jump~ (=C-x r b=).

If you use the =consult= package, its default ~consult-buffer~ command
has the means to group together buffers, recent files, and bookmarks.
Each of those types can be narrowed to with a prefix key.  The package
=consult-dir= is an extension to =consult= which provides useful extras
for working with directories, including bookmarks.

** Treat your notes as a project
:PROPERTIES:
:CUSTOM_ID: h:fad3eb08-ddc7-43e4-ba28-210d89668037
:END:

Emacs has a built-in library for treating a directory tree as a
"project".  This means that the contents of this tree are seen as part
of the same set, so commands like ~project-switch-to-buffer~ (=C-x p b=
by default) will only consider buffers in the current project
(e.g. three notes that are currently being visited).

Normally, a "project" is a directory tree whose root is under version
control.  For our purposes, all you need is to navigate to the
~denote-directory~ (for the shell or via Dired) and use the command-line
to run this (requires the =git= executable):

: git init

From Dired, you can type =M-!= which invokes ~dired-smart-shell-command~
and then run the git call there.

The project can then be registered by invoking any project-related
command inside of it, such as ~project-find-file~ (=C-x p f=).

It is a good idea to keep your notes under version control, as that
gives you a history of changes for each file.  We shall not delve into
the technicalities here, though suffice to note that Emacs' built-in
version control framework or the exceptionally well-crafted =magit=
package will get the job done (VC can work with other backends besides
Git).

** Use the tree-based file prompt for select commands
:PROPERTIES:
:CUSTOM_ID: h:8f9e0971-8b30-4e7b-af79-8fed257dbcfa
:END:

Older versions of Denote had a file prompt that resembled that of the
standard ~find-file~ command (bound to =C-x C-f= by default).  This
means that it used a tree-based method of navigating the filesystem by
selecting the specific directory and then the given file.

Currently, Denote flattens the file prompt so that every file in the
~denote-directory~ and its subdirectories can be matched from anywhere
using the power of Emacs' minibuffer completion (such as with the help
of the ~orderless~ package in addition to built-in options).

Users who need the old behaviour on a per-command basis can define
their own wrapper functions as shown in the following code block.

#+begin_src emacs-lisp
;; This is the old `denote-file-prompt' that we renamed to
;; `denote-file-prompt-original' for clarity.
(defun denote-file-prompt-original (&optional initial-text)
  "Prompt for file with identifier in variable `denote-directory'.
With optional INITIAL-TEXT, use it to prepopulate the minibuffer."
  (read-file-name "Select note: " (denote-directory) nil nil initial-text
                  (lambda (f)
                    (or (denote-file-has-identifier-p f)
                        (file-directory-p f)))))

;; Our wrapper command that changes the current `denote-file-prompt'
;; to the functionality of `denote-file-prompt-original' only when
;; this command is used.
(defun my-denote-link ()
  "Call `denote-link' but use Denote's original file prompt.
See `denote-file-prompt-original'."
  (interactive)
  (cl-letf (((symbol-function 'denote-file-prompt) #'denote-file-prompt-original))
    (call-interactively #'denote-link)))
#+end_src

** Rename files with Denote in the Image Dired thumbnails buffer
:PROPERTIES:
:CUSTOM_ID: h:e666ced6-da75-4bdb-9be3-82c2f4455ee9
:END:

[[#h:2d5ee9bf-e8f2-426c-8bf7-bf78bc88d1ee][Rename files with Denote using ~dired-preview~]]

Just as with the ~denote-dired-rename-marked-files-with-keywords~,
we can use Denote in the Image Dired buffer ([[#h:1b6b2c78-42f0-45b8-9ef0-6de21a8b2cde][Rename multiple files at once]]).
Here is the custom code:

#+begin_src emacs-lisp
(autoload 'image-dired--with-marked "image-dired")
(autoload 'image-dired-original-file-name "image-dired-util")

(defun my-denote-image-dired-rename-marked-files (keywords)
  "Like `denote-dired-rename-marked-files-with-keywords' but for Image Dired.
Prompt for KEYWORDS and rename all marked files in the Image
Dired buffer to have a Denote-style file name with the given
KEYWORDS.

IMPORTANT NOTE: if there are marked files in the corresponding
Dired buffers, those will be targeted as well.  This is not the
fault of Denote: it is how Dired and Image Dired work in tandem.
To only rename the marked thumbnails, start by unmarking
everything in Dired.  Then mark the items in Image Dired and
invoke this command."
  (interactive (list (denote-keywords-prompt)) image-dired-thumbnail-mode)
  (image-dired--with-marked
   (when-let* ((file (image-dired-original-file-name))
               (dir (file-name-directory file))
               (id (or (denote-retrieve-filename-identifier file) ""))
               (file-type (denote-filetype-heuristics file))
               (title (denote--retrieve-title-or-filename file file-type))
               (signature (or (denote-retrieve-filename-signature file) "")
               (extension (file-name-extension file t))
               (new-name (denote-format-file-name dir id keywords title extension signature))
               (default-directory dir))
     (denote-rename-file-and-buffer file new-name))))
#+end_src

While the ~my-denote-image-dired-rename-marked-files~ renames files in
the helpful Denote-compliant way, users may still need to not prepend
a unique identifier and not sluggify (hyphenate and downcase) the
image's existing file name.  To this end, the following custom command
can be used instead:

#+begin_src emacs-lisp
(defun my-image-dired-rename-marked-files (keywords)
  "Like `denote-dired-rename-marked-files-with-keywords' but for Image Dired.
Prompt for keywords and rename all marked files in the Image
Dired buffer to have Denote-style keywords, but none of the other
conventions of Denote's file-naming scheme."
  (interactive (list (denote-keywords-prompt)) image-dired-thumbnail-mode)
  (image-dired--with-marked
   (when-let* ((file (image-dired-original-file-name))
               (dir (file-name-directory file))
               (file-type (denote-filetype-heuristics file))
               (title (denote--retrieve-title-or-filename file file-type))
               (extension (file-name-extension file t))
               (kws (denote--keywords-combine keywords))
               (new-name (concat dir title "__" kws extension))
               (default-directory dir))
     (denote-rename-file-and-buffer file new-name))))
#+end_src

** Rename files with Denote using ~dired-preview~
:PROPERTIES:
:CUSTOM_ID: h:2d5ee9bf-e8f2-426c-8bf7-bf78bc88d1ee
:END:

The ~dired-preview~ package (by me/Protesilaos) automatically displays
a preview of the file at point in Dired.  This can be helpful in
tandem with Denote when we want to rename multiple files by taking a
quick look at their contents.

The command ~denote-dired-rename-marked-files-with-keywords~
will generate Denote-style file names based on the keywords it prompts
for. Identifiers are derived from each file's modification date
([[#h:1b6b2c78-42f0-45b8-9ef0-6de21a8b2cde][Rename multiple files at once]]). There is no need for any custom code
in this scenario.

As noted in the section about Image Dired, the user may sometimes not
need a fully fledged Denote-style file name but only append Denote-like
keywords to each file name (e.g. =Original Name__denote_test.jpg=
instead of =20230710T195843--original-name__denote_test.jpg=).

[[#h:e666ced6-da75-4bdb-9be3-82c2f4455ee9][Rename files with Denote in the Image Dired thumbnails buffer]]

In such a workflow, it is unlikely to be dealing with ordinary text
files where front matter can be helpful.  A custom command does not
need to behave like what Denote provides out-of-the-box, but can
instead append keywords to file names without conducting any further
actions.  We thus have:

#+begin_src emacs-lisp
(defun my-denote-dired-rename-marked-files-keywords-only ()
  "Like `denote-dired-rename-marked-files-with-keywords' but only for keywords in file names.

Prompt for keywords and rename all marked files in the Dired
buffer to only have Denote-style keywords, but none of the other
conventions of Denote's file-naming scheme."
  (interactive nil dired-mode)
  (if-let* ((marks (dired-get-marked-files)))
      (let ((keywords (denote-keywords-prompt)))
        (dolist (file marks)
          (let* ((dir (file-name-directory file))
                 (file-type (denote-filetype-heuristics file))
                 (title (denote--retrieve-title-or-filename file file-type))
                 (extension (file-name-extension file t))
                 (kws (denote--keywords-combine keywords))
                 (new-name (concat dir title "__" kws extension)))
            (denote-rename-file-and-buffer file new-name)))
        (revert-buffer))
    (user-error "No marked files; aborting")))
#+end_src

** Avoid duplicate identifiers when exporting Denote notes
:PROPERTIES:
:CUSTOM_ID: h:4a8c4546-26b3-4195-8b2c-b08a519986a4
:END:

When exporting Denote notes to, for example, an HTML or PDF file,
there is a high probability that the same file name is used with a new
extension.  This is problematic because it creates files with
duplicate identifiers.  The =20230515T085612--example__keyword.org=
produces a =20230515T085612--example__keyword.pdf=.  Any link to the
=20230515T085612= will thus break: it does not honor Denote's
expectation of finding unique identifiers.  This is not the fault of
Denote: exporting is done by the user without Denote's involvement.

Org Mode and Markdown use different approaches to exporting files.  No
recommended method is available for plain text files as there is no
standardised export functionality for this format (the user can always
create a new note using the file type they want on a case-by-case
basis: [[#h:887bdced-9686-4e80-906f-789e407f2e8f][Convenience commands for note creation]]).

*** Export Denote notes with Org Mode
:PROPERTIES:
:CUSTOM_ID: h:67669d9d-17c3-45bd-8227-da57d8bc3b73
:END:

Org Mode has a built-in configurable export engine.  You can prevent
duplicate identifiers when exporting manually for each exported file
or by advising the Org export function.

The ~denote-org~ package (by Protesilaos) also provides commands to
convert =denote:= links to their =file:= equivalent, in case this is a
required pre-processing step for export purposes.

**** Manually configure Org export
:PROPERTIES:
:CUSTOM_ID: h:bf791e28-73e5-4ed8-88bc-e4e9b3ebaedb
:END:

Insert =#+export_file_name: FILENAME= in the front matter before
exporting to force a filename called whatever the value of =FILENAME=
is.  The =FILENAME= does not specify the file type extension, such as
=.pdf=.  This is up to the export engine.  For example, a Denote note
with a complete file name of =20230515T085612--example__keyword.org=
and a front matter entry of =#+export_file_name: hello= will be
exported as =hello.pdf=.

The advantage of this manual method is that it gives the user full
control over the resulting file name.  The disadvantage is that it
depends on the user's behaviour.  Forgetting to add a new name can
lead to duplicate identifiers, as already noted in the introduction to
this section ([[#h:4a8c4546-26b3-4195-8b2c-b08a519986a4][Export Denote notes]]).

**** Automatically store Org exports in another folder
:PROPERTIES:
:CUSTOM_ID: h:7a61a370-78e5-42a1-9650-98fee140723f
:END:

It is possible to automatically place all exports in another folder by
making Org's function ~org-export-output-file-name~ create the target
directory if needed and move the exported file there.  Remember that
advising Elisp code must be handled with care, as it might break the
original function in subtle ways.

#+begin_src emacs-lisp
(defvar my-org-export-output-directory-prefix "./export_"
  "Prefix of directory used for org-mode export.

The single dot means that the directory is created on the same
level as the one where the Org file that performs the exporting
is.  Use two dots to place the directory on a level above the
current one.

If this directory is part of `denote-directory', make sure it is
not read by Denote.  See `denote-excluded-directories-regexp'.
This way there will be no known duplicate Denote identifiers
produced by the Org export mechanism.")

(defun my-org-export-create-directory (fn extension &rest args)
  "Move Org export file to its appropriate directory.

Append the file type EXTENSION of the exported file to
`my-org-export-output-directory-prefix' and, if absent, create a
directory named accordingly.

Install this as advice around `org-export-output-file-name'.  The
EXTENSION is supplied by that function.  ARGS are its remaining
arguments."
  (let ((export-dir (format "%s%s" my-org-export-output-directory-prefix extension)))
    (unless (file-directory-p export-dir)
      (make-directory export-dir)))
  (apply fn extension args))

(advice-add #'org-export-output-file-name :around #'my-org-export-create-directory)
#+end_src

The target export directory should not be a subdirectory of
~denote-directory~, as that will result in duplicate identifiers.
Exclude it with the ~denote-excluded-directories-regexp~ user option
([[#h:8458f716-f9c2-4888-824b-2bf01cc5850a][Exclude certain directories from all operations]]).

[ NOTE: I (Protesilaos) am not a LaTeX user and cannot test the
  following. ]

Using a different directory will require some additional configuration
when exporting using LaTeX.  The export folder cannot be inside the
path of the ~denote-directory~ to prevent Denote from recognising it
as an attachment:
<https://emacs.stackexchange.com/questions/45751/org-export-to-different-directory>.

**** Org Mode Publishing
:PROPERTIES:
:CUSTOM_ID: h:2f3451ed-2fc4-4f36-bcf2-112939963e20
:END:

Org Mode also has a publishing tool for exporting a collection of
files. Some user might apply this approach to convert their note
collection to a public or private website.

The ~org-publish-project-alist~ variable drives the publishing
process, including the publishing directory.

The publishing directory should not be a subdirectory of
~denote-directory~, as that will result in duplicate identifiers.
Exclude it with the ~denote-excluded-directories-regexp~ user option
([[#h:8458f716-f9c2-4888-824b-2bf01cc5850a][Exclude certain directories from all operations]]).

*** Export Denote notes with Markdown
:PROPERTIES:
:CUSTOM_ID: h:44c6a34a-e9ad-4f43-a24f-12f2c5a8467e
:END:

Exporting from Markdown requires an external processor (e.g.,
Markdown.pl, Pandoc, or MultiMarkdown).  The ~markdown-command~
variable defines the command line used in export, for example:

#+begin_src emacs-lisp
(setq markdown-command "multimarkdown")
#+end_src

The export process thus occurs outside of Emacs.  Users need to read
the documentation of their preferred processor to prevent the creation
of duplicate Denote identifiers.

** Set up your workflow for daily or weekly meeting notes
:PROPERTIES:
:CUSTOM_ID: h:00998f94-0194-43ef-b349-260106ef7177
:END:

Perhaps as part of work, we meet with certain people on a regular
basis. During the meeting we may discuss a variety of topics. How best
to approach with the help of Denote?

One option is to write a new file for each meeting, giving it the
appropriate keywords each time ([[#h:17896c8c-d97a-4faa-abf6-31df99746ca6][Points of entry]]). This is what Denote
does by default and does not need any further tweaks. If we need to
review those notes, we can use the command ~denote-sort-dired~
([[#h:9fe01e63-f34f-4479-8713-f162a5ca865e][Sort files by component]]), or one of the Org dynamic blocks we provide
([[#h:8b542c50-dcc9-4bca-8037-a36599b22779][Use Org dynamic blocks]]), among other options.

Another approach is to write one file per person with the regular
~denote~ command (or related), give it the name of the person as a
title and, optionally, use some relevant keywords. Inside each file,
write a top-level heading with the date of the meeting, and then
produce the meeting notes below as paragraphs and subheadings. This
can all be done without any changes to Denote, though we can
streamline it by incorporating the following code in our setup.
Configure ~my-denote-colleagues~ and then use the command
~my-denote-colleagues-new-meeting~ to see how it works.

#+begin_src emacs-lisp
(defvar my-denote-colleagues '("Prot" "Protesilaos")
  "List of names I collaborate with.
There is at least one file in the variable `denote-directory' that has
the name of this person.")

(defvar my-denote-colleagues-prompt-history nil
  "Minibuffer history for `my-denote-colleagues-new-meeting'.")

(defun my-denote-colleagues-prompt ()
  "Prompt with completion for a name among `my-denote-colleagues'.
Use the last input as the default value."
  (let ((default-value (car my-denote-colleagues-prompt-history)))
    (completing-read
     (format-prompt "New meeting with COLLEAGUE" default-value)
     my-denote-colleagues
     nil :require-match nil
     'my-denote-colleagues-prompt-history
     default-value)))

(defun my-denote-colleagues-get-file (name)
  "Find file in variable `denote-directory' for NAME colleague.
If there are more than one files, prompt with completion for one among
them.

NAME is one among `my-denote-colleagues'."
  (if-let* ((files (denote-directory-files name))
            (length-of-files (length files)))
      (cond
       ((= length-of-files 1)
        (car files))
       ((> length-of-files 1)
        (completing-read "Select a file: " files nil :require-match)))
    (user-error "No files for colleague with name `%s'" name)))

(defun my-denote-colleagues-new-meeting ()
  "Prompt for the name of a colleague and insert a timestamped heading therein.
The name of a colleague corresponds to at least one file in the variable
`denote-directory'.  In case there are multiple files, prompt to choose
one among them and operate therein."
  (declare (interactive-only t))
  (interactive)
  (let* ((name (my-denote-colleagues-prompt))
         (file (my-denote-colleagues-get-file name))
         (time (format-time-string "%F %a %R")))  ; remove %R if you do not want the time
    (with-current-buffer (find-file file)
      (goto-char (point-max))
      ;; Here I am assuming we are in `org-mode', hence the leading
      ;; asterisk for the heading.  Adapt accordingly.
      (insert (format "* [%s]\n\n" time)))))
#+end_src

* For developers or advanced users
:PROPERTIES:
:CUSTOM_ID: h:c916d8c5-540a-409f-b780-6ccbd90e088e
:END:

Denote is in a stable state and can be relied upon as the basis for
custom extensions ([[#h:08b14682-e73f-4b11-b2e2-be3b788c8572][Packages that build on Denote]]). Further below is a
list with the functions or variables we provide for public usage.
Those are in addition to all user options and commands that are
already documented in the various sections of this manual.

In this context "public" is any form with single hyphens in its symbol,
such as ~denote-directory-files~.  We expressly support those, meaning
that we consider them reliable and commit to documenting any changes in
their particularities (such as through ~make-obsolete~, a record in the
change log, a blog post on the maintainer's website, and the like).

By contradistinction, a "private" form is declared with two hyphens in
its symbol such as ~denote--file-extension~.  Do not use those as we
might change them without further notice.

The following sections cover the specifics.

** Common building blocks for developers or advanced users
:PROPERTIES:
:CUSTOM_ID: h:c98aed45-341a-40a0-91ce-347a29c98ab4
:END:

#+vindex: denote-date-identifier-format
+ Variable ~denote-date-identifier-format~ :: Format of ID prefix of a note's
  filename.  The note's ID is derived from the date and time of its
  creation ([[#h:4e9c7512-84dc-4dfb-9fa9-e15d51178e5d][The file-naming scheme]]).

#+vindex: denote-date-identifier-regexp
+ Variable ~denote-date-identifier-regexp~ :: Regular expression to match
  ~denote-date-identifier-format~.

#+vindex: denote-signature-regexp
+ Variable ~denote-signature-regexp~ :: Regular expression to match
  the =SIGNATURE= field in a file name.

#+vindex: denote-title-regexp
+ Variable ~denote-title-regexp~ :: Regular expression to match the
  =TITLE= field in a file name ([[#h:4e9c7512-84dc-4dfb-9fa9-e15d51178e5d][The file-naming scheme]]).

#+vindex: denote-keywords-regexp
+ Variable ~denote-keywords-regexp~ :: Regular expression to match the
  =KEYWORDS= field in a file name ([[#h:4e9c7512-84dc-4dfb-9fa9-e15d51178e5d][The file-naming scheme]]).

#+findex: denote-date-identifier-p
+ Function ~denote-date-identifier-p~ :: Return non-nil if =IDENTIFIER=
  string is a Denote date identifier.

#+findex: denote-file-is-note-p
+ Function ~denote-file-is-note-p~ :: Return non-nil if =FILE= is an
  actual Denote note. For our purposes, a note must satisfy
  ~file-regular-p~ and ~denote-filename-is-note-p~.

#+findex: denote-file-has-identifier-p
+ Function ~denote-file-has-identifier-p~ :: Return non-nil if =FILE=
  has a Denote identifier.

#+findex: denote-file-has-denoted-filename-p
+ Function ~denote-file-has-denoted-filename-p~ :: Return non-nil if
  =FILE= respects the file-naming scheme of Denote. This tests the
  rules of Denote's file-naming scheme. Sluggification is ignored. It
  is done by removing all file name components and validating what
  remains.

#+findex: denote-file-has-signature-p
+ Function ~denote-file-has-signature-p~ :: Return non-nil if =FILE=
  has a signature.

#+findex: denote-file-has-supported-extension-p
+ Function ~denote-file-has-supported-extension-p~ :: Return non-nil
  if =FILE= has supported extension.  Also account for the possibility
  of an added =.gpg= suffix. Supported extensions are those implied by
  ~denote-file-type~.

#+findex: denote-file-is-writable-and-supported-p
+ Function ~denote-file-is-writable-and-supported-p~ :: Return non-nil
  if =FILE= is writable and has supported extension.

#+findex: denote-file-type-extensions
+ Function ~denote-file-type-extensions~ :: Return all file type
  extensions in ~denote-file-types~.

#+vindex: denote-encryption-file-extensions
+ Variable ~denote-encryption-file-extensions~ :: List of strings
  specifying file extensions for encryption.

#+findex: denote-file-type-extensions-with-encryption
+ Function ~denote-file-type-extensions-with-encryption~ :: Derive
  ~denote-file-type-extensions~ plus ~denote-encryption-file-extensions~.

#+findex: denote-get-file-extension
+ Function ~denote-get-file-extension~ :: Return extension of =FILE=
  with dot included.  Account for ~denote-encryption-file-extensions~.
  In other words, return something like =.org.gpg= if it is part of
  the file, else return =.org=.

#+findex: denote-get-file-extension-sans-encryption
+ Function ~denote-get-file-extension-sans-encryption~ :: Return
  extension of =FILE= with dot included and without the encryption
  part.  Build on top of ~denote-get-file-extension~ though always
  return something like =.org= even if the actual file extension is
  =.org.gpg=.

#+findex: denote-infer-keywords-from-files
+ Functions ~denote-infer-keywords-from-files~ :: Return list of
  keywords in ~denote-directory-files~. With optional
  =FILES-MATCHING-REGEXP=, only extract keywords from the matching
  files. Otherwise, do it for all files. Keep any duplicates. Users
  who do not want duplicates should refer to the functions
  ~denote-keywords~.

#+findex: denote-keywords
+ Function ~denote-keywords~ :: Return appropriate list of keyword
  candidates. If ~denote-infer-keywords~ is non-nil, infer keywords
  from existing notes and combine them into a list with
  ~denote-known-keywords~. Else use only the latter set of keywords
  ([[#h:6a92a8b5-d766-42cc-8e5b-8dc255466a23][Standard note creation]]). In the case of keyword inferrence, use
  optional =FILES-MATCHING-REGEXP=, to extract keywords only from the
  matching files. Otherwise, do it for all files. Filter inferred
  keywords with the user option ~denote-keywords-to-not-infer-regexp~.
  [ The ~denote-excluded-keywords-regexp~ is an obsolete alias for
    ~denote-keywords-to-not-infer-regexp~ as part of {{{development-version}}}. ]

#+findex: denote-keywords-sort
+ Function ~denote-keywords-sort~ :: Sort =KEYWORDS= if
  ~denote-sort-keywords~ is non-nil.  =KEYWORDS= is a list of strings,
  per ~denote-keywords-prompt~.

#+findex: denote-keywords-combine
+ Function ~denote-keywords-combine~ :: Combine =KEYWORDS= list of
  strings into a single string. Keywords are separated by the
  underscore character, per the Denote file-naming scheme.

#+findex: denote-valid-date-p
+ Function ~denote-valid-date-p~ :: Return =DATE= as a valid date. A
  valid =DATE= is a value that can be parsed by either ~decode-time~
  or ~date-to-time~ .Those functions signal an error if =DATE= is a
  value they do not recognise. If =DATE= is nil, return nil.

#+findex: denote-directories
+ Function ~denote-directories~ :: Return list of paths to the
  variable ~denote-directory~.

#+findex: denote-directories-get-common-root
+ Function ~denote-directories-get-common-root~ :: Return the closest
  common root of the ~denote-directories~.

#+findex: denote-directory-get-files
+ Function ~denote-directory-get-files~ :: Return list with full path
  of valid files in variable ~denote-directory~. Consider files that
  satisfy ~denote-file-has-identifier-p~ and are not backups.

#+vindex: denote-directory-get-files-function
+ Variable ~denote-directory-get-files-function~ :: Function to return
  list of Denote files. Each file is a string representing an absolute
  file system path. This is intended for use in the function
  ~denote-directory-files~.

#+findex: denote-directory-files
+ Function ~denote-directory-files~ :: Return list of absolute file
  paths in variable ~denote-directory~. Files that match
  ~denote-excluded-files-regexp~ are excluded from the list. Files
  only need to have an identifier. The return value may thus include
  file types that are not implied by ~denote-file-type~. With optional
  =FILES-MATCHING-REGEXP=, restrict files to those matching the given
  regular expression. With optional =OMIT-CURRENT= as a non-nil value,
  do not include the current Denote file in the returned list. With
  optional =TEXT-ONLY= as a non-nil value, limit the results to text
  files that satisfy ~denote-file-is-note-p~. With optional
  =EXCLUDE-REGEXP= exclude the files that match the given regular
  expression. This is done after =FILES-MATCHING-REGEXP= and
  =OMIT-CURRENT= have been applied.

#+findex: denote-directory-subdirectories
+ Function ~denote-directory-subdirectories~ :: Return list of
  subdirectories in variable ~denote-directory~. Omit dotfiles (such
  as .git) unconditionally.  Also exclude whatever matches
  ~denote-excluded-directories-regexp~.  Note that the
  ~denote-directory~ accepts a directory-local value for what we call
  "silos" ([[#h:15719799-a5ff-4e9a-9f10-4ca03ef8f6c5][Maintain separate directories for notes]]).

#+findex: denote-id-to-date
+ Function ~denote-id-to-date~ :: Convert =IDENTIFIER= to a date
  string of the form =YYYY-MM-DD=.

** Predefined note values for developers or advanced users
:PROPERTIES:
:CUSTOM_ID: h:a8b9082c-8bd5-492d-8da7-4f41ee493d59
:END:

In custom code, it is possible to override what the ~denote~ command
is reading by specifying a value for the following. In that case,
there will be no corresponding prompt.

#+findex: denote-use-date
+ Function ~denote-use-date~ :: The date to be used in a note creation
  command. See the documentation of ~denote~ for acceptable values.
  This variable is ignored if nil. Only ever ~let~ bind this,
  otherwise the title will always be the same and the title prompt
  will be skipped.

#+findex: denote-use-directory
+ Function ~denote-use-directory~ :: The directory to be used in a
  note creation command. See the documentation of ~denote~ for
  acceptable values. This variable is ignored if nil. Only ever ~let~
  bind this, otherwise the title will always be the same and the title
  prompt will be skipped.

#+findex: denote-use-file-type
+ Function ~denote-use-file-type~ :: The file type to be used in a
  note creation command. See the documentation of ~denote~ for
  acceptable values. This variable is ignored if nil. Only ever ~let~
  bind this, otherwise the title will always be the same and the title
  prompt will be skipped.

#+findex: denote-use-keywords
+ Function ~denote-use-keywords~ :: The keywords to be used in a note
  creation command. See the documentation of ~denote~ for acceptable
  values. This variable is ignored if ~default~. Only ever ~let~ bind this,
  otherwise the title will always be the same and the title prompt
  will be skipped.

#+findex: denote-use-signature
+ Function ~denote-use-signature~ :: The signature to be used in a
  note creation command. See the documentation of ~denote~ for
  acceptable values. This variable is ignored if nil. Only ever ~let~
  bind this, otherwise the title will always be the same and the title
  prompt will be skipped.

#+findex: denote-use-template
+ Function ~denote-use-template~ :: The template to be used in a note
  creation command. See the documentation of ~denote~ for acceptable
  values. This variable is ignored if nil. Only ever ~let~ bind this,
  otherwise the title will always be the same and the title prompt
  will be skipped.

#+findex: denote-use-title
+ Function ~denote-use-title~ :: The title to be used in a note
  creation command. See the documentation of ~denote~ for acceptable
  values. This variable is ignored if nil. Only ever ~let~ bind this,
  otherwise the title will always be the same and the title prompt
  will be skipped.

** File path interface for developers or advanced users
:PROPERTIES:
:CUSTOM_ID: h:08e696e4-c9e1-48b4-8349-e53451aed1df
:END:

#+findex: denote-file-name-relative-to-denote-directory
+ Function ~denote-file-name-relative-to-denote-directory~ :: Return
  name of =FILE= relative to the variable ~denote-directory~.  =FILE=
  must be an absolute path.

#+findex: denote-slug-keep-only-ascii
+ Function ~denote-slug-keep-only-ascii~ :: Remove all non-ASCII
  characters from =STR= and replace them with spaces. This is useful
  as a helper function to construct ~denote-file-name-slug-functions~
  ([[#h:d1e4eb5b-e7f2-4a3b-9243-e1c653817a4a][Custom sluggification to remove non-ASCII characters]]).

#+findex: denote-sluggify
#+findex: denote-sluggify-and-apply-rules
+ Function ~denote-sluggify-and-apply-rules~ (alias ~denote-sluggify~) :: Make
  =STR= an appropriate slug for file name =COMPONENT= ([[#h:ae8b19a1-7f67-4258-96b3-370a72c43f4e][Sluggification of file name components]]).
  Apply the function specified in ~denote-file-name-slug-function~ to
  =COMPONENT= which is one of =title=, =signature=, =keyword=. If the
  resulting string still contains consecutive =-=,=_= or ~=~, they are
  replaced by a single occurence of the character, if necessary
  according to =COMPONENT=. If =COMPONENT= is ~keyword~, remove
  underscores from =STR= as they are used as the keywords separator in
  file names. Also enforce the rules of the file-naming scheme.

#+findex: denote-sluggify-keyword
+ Function ~denote-sluggify-keyword~ :: Sluggify =STR= while joining
  separate words.

#+findex: denote-sluggify-signature
+ Function ~denote-sluggify-signature~ :: Make =STR= an appropriate
  slug for signatures ([[#h:ae8b19a1-7f67-4258-96b3-370a72c43f4e][Sluggification of file name components]]).

#+findex: denote-sluggify-keywords-and-apply-rules
+ Function ~denote-sluggify-keywords-and-apply-rules~ :: Sluggify
  =KEYWORDS=, which is a list of strings
  ([[#h:ae8b19a1-7f67-4258-96b3-370a72c43f4e][Sluggification of file name components]]).

#+findex: denote-format-file-name
+ Function ~denote-format-file-name~ :: Format file name. =DIR-PATH=,
  =ID=, =KEYWORDS=, =TITLE=, =EXTENSION= and =SIGNATURE= are expected to
  be supplied by ~denote~ or equivalent command.

  =DIR-PATH= is a string pointing to a directory. It ends with a
  forward slash (the function ~denote-directory~ makes sure this is
  the case when returning the value of the variable ~denote-directory~).
  =DIR-PATH= cannot be nil or an empty string.

  =ID= is a string holding the identifier of the note. It can be an
  empty string, in which case its respective file name component is
  not added to the base file name.

  =DIR-PATH= and =ID= form the base file name.

  =KEYWORDS= is a list of strings that is reduced to a single string
  by ~denote-keywords-combine~. =KEYWORDS= can be an empty list or a
  nil value, in which case the relevant file name component is not
  added to the base file name.

  =TITLE= and =SIGNATURE= are strings. They can be an empty string, in
  which case their respective file name component is not added to the
  base file name.

  =EXTENSION= is a string that contains a dot followed by the file
  type extension. It can be an empty string or a nil value, in which
  case it is not added to the base file name.

** Data retrieval interface for developers or advanced users
:PROPERTIES:
:CUSTOM_ID: h:9b32bf7d-1569-4495-801c-8835f022d72e
:END:

#+vindex: denote-get-identifier-function
+ Variable ~denote-get-identifier-function~ :: The function to
  generate an identifier as a non-empty string. The function takes two
  arguments: an initial identifier and a date. The initial identifier
  is used as a reference to derive a unique variant of it, if possible
  (e.g. to keep incrementing seconds while keeping the rest of the
  date+time the same). Existing identifiers are stored in the variable
  ~denote-used-identifiers~. If the initial identifier is nil or an
  identifier cannot be derived from it, then the date can be used
  instead. The date has the same format as ~current-time~. When it is
  nil, the ~current-time~ is used.

#+findex: denote-get-path-by-id
+ Function ~denote-get-path-by-id~ :: Return absolute path of =ID=
  string in ~denote-directory-files~.

#+findex: denote-get-identifier-at-point
+ Function ~denote-get-identifier-at-point~ :: Return the identifier
  at point or =POINT=.

#+findex: denote-extract-keywords-from-path
+ Function ~denote-extract-keywords-from-path~ :: Extract keywords
  from =PATH= and return them as a list of strings.  =PATH= must be a
  Denote-style file name where keywords are prefixed with an
  underscore.  If =PATH= has no such keywords, which is possible,
  return nil ([[#h:4e9c7512-84dc-4dfb-9fa9-e15d51178e5d][The file-naming scheme]]).

#+findex: denote-extract-id-from-string
+ Function ~denote-extract-id-from-string~ :: Return existing Denote
  identifier in =STRING=, else nil.

#+findex: denote-retrieve-filename-identifier
+ Function ~denote-retrieve-filename-identifier~ :: Extract identifier
  from =FILE= name, if present, else return nil. To create a new one
  from a date, refer to the ~denote-identifier-generation-function~
  variable.

#+findex: denote-retrieve-filename-title
+ Function ~denote-retrieve-filename-title~ ::  Extract Denote title
  component from =FILE= name, if present, else return nil.

#+findex: denote-retrieve-filename-keywords
+ Function ~denote-retrieve-filename-keywords~ ::  Extract keywords
  from =FILE= name, if present, else return nil. Return
  matched keywords as a single string.

#+findex: denote-retrieve-filename-signature
+ Function ~denote-retrieve-filename-signature~ :: Extract signature
  from =FILE= name, if present, else return nil.

#+findex: denote-retrieve-title-or-filename
+ Function ~denote-retrieve-title-or-filename~ :: Return appropriate
  title for =FILE= given its =TYPE=. This is a wrapper for
  ~denote-retrieve-front-matter-title-value~ and
  =denote-retrieve-filename-title=.

#+findex: denote-retrieve-front-matter-title-value
+ Function ~denote-retrieve-front-matter-title-value~ :: Return title value from
  =FILE= front matter per =FILE-TYPE=.

#+findex: denote-retrieve-front-matter-title-line
+ Function ~denote-retrieve-front-matter-title-line~ :: Return title line from
  =FILE= front matter per =FILE-TYPE=.

#+findex: denote-retrieve-front-matter-keywords-value
+ Function ~denote-retrieve-front-matter-keywords-value~ :: Return keywords value
  from =FILE= front matter per =FILE-TYPE=. The return value is a list
  of strings.

#+findex: denote-retrieve-front-matter-keywords-line
+ Function ~denote-retrieve-front-matter-keywords-line~ :: Return keywords line
  from =FILE= front matter per =FILE-TYPE=.

** Prompt interface for developers or advanced users
:PROPERTIES:
:CUSTOM_ID: h:e9d05541-bd00-43b9-8146-8c4445f78f07
:END:

#+findex: denote-add-prompts
+ Function ~denote-add-prompts~ :: Add list of =ADDITIONAL-PROMPTS= to
  ~denote-prompts~. This is best done inside of a ~let~ to create a
  wrapper function around ~denote~, ~denote-rename-file~, and
  generally any command that consults the value of ~denote-prompts~.

#+findex: denote-identifier-prompt
+ Function ~denote-identifier-prompt~ :: Prompt for identifier string.
  With optional =INITIAL-IDENTIFIER= use it as the initial minibuffer
  text. With optional =PROMPT-TEXT= use it in the minibuffer instead
  of the default prompt. Previous inputs at this prompt are available
  for minibuffer completion if the user option ~denote-history-completion-in-prompts~
  is set to a non-nil value ([[#h:403422a7-7578-494b-8f33-813874c12da3][The ~denote-history-completion-in-prompts~ option]]).

#+findex: denote-signature-prompt
+ Function ~denote-signature-prompt~ :: Prompt for signature string.
  With optional =INITIAL-SIGNATURE= use it as the initial minibuffer
  text. With optional =PROMPT-TEXT= use it in the minibuffer instead
  of the default prompt. Previous inputs at this prompt are available
  for minibuffer completion if the user option ~denote-history-completion-in-prompts~
  is set to a non-nil value ([[#h:403422a7-7578-494b-8f33-813874c12da3][The ~denote-history-completion-in-prompts~ option]]).

#+findex: denote-file-prompt
+ Function ~denote-file-prompt~ :: Prompt for file in variable
  ~denote-directory~. Files that match ~denote-excluded-files-regexp~
  are excluded from the list. With optional =FILES-MATCHING-REGEXP=,
  filter the candidates per the given regular expression. With
  optional =PROMPT-TEXT=, use it instead of the default call to select
  a file. With optional =NO-REQUIRE-MATCH= accept the given input
  as-is. Return the absolute path to the matching file.

#+findex: denote-keywords-prompt
+ Function ~denote-keywords-prompt~ :: Prompt for one or more keywords.
  Read entries as separate when they are demarcated by the
  ~crm-separator~, which typically is a comma. With optional
  =PROMPT-TEXT=, use it to prompt the user for keywords. Else use a
  generic prompt. With optional =INITIAL-KEYWORDS= use them as the
  initial minibuffer text.

#+findex: denote-title-prompt
+ Function ~denote-title-prompt~ :: Prompt for title string. With
  optional =INITIAL-TITLE= use it as the initial minibuffer text. With
  optional =PROMPT-TEXT= use it in the minibuffer instead of the
  default prompt. Previous inputs at this prompt are available
  for minibuffer completion if the user option ~denote-history-completion-in-prompts~
  is set to a non-nil value ([[#h:403422a7-7578-494b-8f33-813874c12da3][The ~denote-history-completion-in-prompts~ option]]).

#+vindex: denote-title-prompt-current-default
+ Variable ~denote-title-prompt-current-default~ :: Currently bound
  default title for ~denote-title-prompt~.  Set the value of this
  variable within the lexical scope of a command that needs to supply
  a default title before calling ~denote-title-prompt~ and use
  ~unwind-protect~ to set its value back to nil.

#+findex: denote-file-type-prompt
+ Function ~denote-file-type-prompt~ :: Prompt for ~denote-file-type~.
  Note that a non-nil value other than ~text~, ~markdown-yaml~, and
  ~markdown-toml~ falls back to an Org file type.  We use ~org~ here
  for clarity.

#+findex: denote-date-prompt
+ Function ~denote-date-prompt~ :: Prompt for date, expecting
  =YYYY-MM-DD= or that plus =HH:MM= (or even =HH:MM:SS=). Use Org's
  more advanced date selection utility if the user option
  ~denote-date-prompt-use-org-read-date~ is non-nil. It requires Org
  ([[#h:e7ef08d6-af1b-4ab3-bb00-494a653e6d63][The denote-date-prompt-use-org-read-date option]]). With optional
  =INITIAL-DATE= use it as the initial minibuffer text. With optional
  =PROMPT-TEXT= use it in the minibuffer instead of the default
  prompt. =INITIAL-DATE= is a string that can be processed by
  ~denote-valid-date-p~, a value that can be parsed by ~decode-time~
  or nil.

#+findex: denote-command-prompt
+ Function ~denote-command-prompt~ ::  Prompt for command among
  ~denote-commands-for-new-notes~ ([[#h:17896c8c-d97a-4faa-abf6-31df99746ca6][Points of entry]]).

#+vindex: denote-prompts-with-history-as-completion
+ Variable ~denote-prompts-with-history-as-completion~ :: Prompts that
  conditionally perform completion against their history. These are
  minibuffer prompts that ordinarily accept a free form string input,
  as opposed to matching against a predefined set. These prompts can
  optionally perform completion against their own minibuffer history
  when the user option ~denote-history-completion-in-prompts~ is set
  to a non-nil value ([[#h:403422a7-7578-494b-8f33-813874c12da3][The ~denote-history-completion-in-prompts~ option]]).

#+findex: denote-files-matching-regexp-prompt
+ Function ~denote-files-matching-regexp-prompt~ ::  Prompt for
  =REGEXP= to filter Denote files by. With optional =PROMPT-TEXT= use
  it instead of a generic prompt.

#+findex: denote-template-prompt
+ Function ~denote-template-prompt~ :: Prompt for template key in
  ~denote-templates~ and return its value.

#+findex: denote-subdirectory-prompt
+ Function ~denote-subdirectory-prompt~ :: Prompt for subdirectory of
  the variable ~denote-directory~.  The table uses the ~file~
  completion category (so it works with packages such as ~marginalia~
  and ~embark~).

** Front matter interface for developers or advanced users
:PROPERTIES:
:CUSTOM_ID: h:80ddc044-5c64-4fb3-b4f4-2eaf6bceda3b
:END:

#+findex: denote-filetype-heuristics
+ Function ~denote-filetype-heuristics~ :: Return likely file type of
  =FILE=. If in the process of ~org-capture~, consider the file type to
  be that of Org. Otherwise, use the file extension to detect the file
  type of =FILE=.

  If more than one file type correspond to this file extension, use
  the first file type for which the :title-key-regexp in
  ~denote-file-types~ matches in the file.

  Return nil if the file type is not recognized.

#+vindex: denote-org-front-matter
+ Variable ~denote-org-front-matter~ :: Specifies the Org front
  matter.  It is passed to ~format~ with arguments =TITLE=, =DATE=,
  =KEYWORDS=, =ID= ([[#h:7f918854-5ed4-4139-821f-8ee9ba06ad15][Change the front matter format]])

#+vindex: denote-yaml-front-matter
+ Variable ~denote-yaml-front-matter~ :: Specifies the YAML (Markdown)
  front matter.  It is passed to ~format~ with arguments =TITLE=,
  =DATE=, =KEYWORDS=, =ID= ([[#h:7f918854-5ed4-4139-821f-8ee9ba06ad15][Change the front matter format]])

#+vindex: denote-toml-front-matter
+ Variable ~denote-toml-front-matter~ :: Specifies the TOML (Markdown)
  front matter.  It is passed to ~format~ with arguments =TITLE=,
  =DATE=, =KEYWORDS=, =ID= ([[#h:7f918854-5ed4-4139-821f-8ee9ba06ad15][Change the front matter format]])

#+vindex: denote-text-front-matter
+ Variable ~denote-text-front-matter~ :: Specifies the plain text
  front matter.  It is passed to ~format~ with arguments =TITLE=,
  =DATE=, =KEYWORDS=, =ID= ([[#h:7f918854-5ed4-4139-821f-8ee9ba06ad15][Change the front matter format]])

#+findex: denote-date-org-timestamp
+ Function ~denote-date-org-timestamp~ :: Format =DATE= using the Org
  inactive timestamp notation.

#+findex: denote-date-rfc3339
+ Function ~denote-date-rfc3339~ :: Format =DATE= using the RFC3339
  specification.

#+findex: denote-date-iso-8601
+ Function ~denote-date-iso-8601~ :: Format =DATE= according to ISO
  8601 standard.

#+findex: denote-trim-whitespace
+ Function ~denote-trim-whitespace~ :: Trim whitespace around string
  =S=.  This can be used in ~denote-file-types~ to format front
  mattter.

#+findex: denote-trim-whitespace-then-quotes
+ Function ~denote-trim-whitespace-then-quotes~ :: Trim whitespace
  then quotes around string =S=.  This can be used in
  ~denote-file-types~ to format front mattter.

#+findex: denote-format-string-for-org-front-matter
+ Function ~denote-format-string-for-org-front-matter~ :: Return
  string =S= as-is for Org or plain text front matter. If =S= is not a
  string, return an empty string.

#+findex: denote-format-string-for-md-front-matter
+ Function ~denote-format-string-for-md-front-matter~ :: Surround
  string =S= with quotes. If =S= is not a string, return a literal
  emptry string. This can be used in ~denote-file-types~ to format
  front mattter.

#+findex: denote-format-keywords-for-md-front-matter
+ Function ~denote-format-keywords-for-md-front-matter~ :: Format
  front matter =KEYWORDS= for markdown file type.  =KEYWORDS= is a
  list of strings.  Consult the ~denote-file-types~ for how this is
  used.

#+findex: denote-format-keywords-for-text-front-matter
+ Function ~denote-format-keywords-for-text-front-matter~ :: Format
  front matter =KEYWORDS= for text file type.  =KEYWORDS= is a list of
  strings.  Consult the ~denote-file-types~ for how this is used.

#+findex: denote-format-keywords-for-org-front-matter
+ Function ~denote-format-keywords-for-org-front-matter~ :: Format
  front matter =KEYWORDS= for org file type.  =KEYWORDS= is a list of
  strings.  Consult the ~denote-file-types~ for how this is used.

#+findex: denote-extract-keywords-from-front-matter
+ Function ~denote-extract-keywords-from-front-matter~ :: Format front
  matter =KEYWORDS= for org file type.  =KEYWORDS= is a list of
  strings.  Consult the ~denote-file-types~ for how this is used.

#+vindex: denote-file-types
+ Variable ~denote-file-types~ :: Alist of ~denote-file-type~ and
  their format properties.

  Each element is of the form =(SYMBOL PROPERTY-LIST)=.  =SYMBOL= is
  one of those specified in ~denote-file-type~ or an arbitrary symbol
  that defines a new file type.

  =PROPERTY-LIST= is a plist that consists of the following elements:

  1. =:extension= is a string with the file extension including the
     period.

  2. =:date-function= is a function that can format a date.  See the
     functions ~denote--date-iso-8601~, ~denote--date-rfc3339~, and
     ~denote--date-org-timestamp~.

  3. =:front-matter= is either a string passed to ~format~ or a
     variable holding such a string.  The ~format~ function accepts
     four arguments, which come from ~denote~ in this order: =TITLE=,
     =DATE=, =KEYWORDS=, =IDENTIFIER=.  Read the doc string of
     ~format~ on how to reorder arguments.

  4. =:title-key-regexp= is a regular expression that is used to
     retrieve the title line in a file.  The first line matching this
     regexp is considered the title line.

  5. =:title-value-function= is the function used to format the raw
     title string for inclusion in the front matter (e.g. to surround
     it with quotes).  Use the ~identity~ function if no further
     processing is required.

  6. =:title-value-reverse-function= is the function used to retrieve
     the raw title string from the front matter.  It performs the
     reverse of =:title-value-function=.

  7. =:keywords-key-regexp= is a regular expression used to retrieve
     the keywords' line in the file.  The first line matching this
     regexp is considered the keywords' line.

  8. =:keywords-value-function= is the function used to format the
     keywords' list of strings as a single string, with appropriate
     delimiters, for inclusion in the front matter.

  9. =:keywords-value-reverse-function= is the function used to retrieve
     the keywords' value from the front matter.  It performs the reverse
     of the =:keywords-value-function=.

  10. =:link= is a string, or variable holding a string, that
      specifies the format of a link.  See the variables
      ~denote-org-link-format~, ~denote-md-link-format~.

  11. =:link-in-context-regexp= is a regular expression that is used
      to match the aforementioned link format.  See the variables
      ~denote-org-link-in-context-regexp~, ~denote-md-link-in-context-regexp~.

  If ~denote-file-type~ is nil, use the first element of this list for
  new note creation.  The default is ~org~.

** Link interface for developers or advanced users
:PROPERTIES:
:CUSTOM_ID: h:97b8eb9e-07e1-4992-8b59-2a0e3b65574b
:END:

#+vindex: denote-org-link-format
+ Variable ~denote-org-link-format~ :: Format of Org link to note.
  The value is passed to ~format~ with =IDENTIFIER= and =TITLE=
  arguments, in this order.  Also see ~denote-org-link-in-context-regexp~.

#+vindex: denote-md-link-format
+ Variable ~denote-md-link-format~ :: Format of Markdown link to note.
  The =%N$s= notation used in the default value is for ~format~ as the
  supplied arguments are =IDENTIFIER= and =TITLE=, in this order.
  Also see ~denote-md-link-in-context-regexp~.

#+vindex: denote-id-only-link-format
+ Variable ~denote-id-only-link-format~ :: Format of identifier-only
  link to note.  The value is passed to ~format~ with =IDENTIFIER= as
  its sole argument.    Also see ~denote-id-only-link-in-context-regexp~.

#+vindex: denote-org-link-in-context-regexp
+ Variable ~denote-org-link-in-context-regexp~ :: Regexp to match an
  Org link in its context.  The format of such links is ~denote-org-link-format~.

#+vindex: denote-md-link-in-context-regexp
+ Variable ~denote-md-link-in-context-regexp~ :: Regexp to match an
  Markdown link in its context.  The format of such links is ~denote-md-link-format~.

#+vindex: denote-id-only-link-in-context-regexp
+ Variable ~denote-id-only-link-in-context-regexp~ :: Regexp to match
  an identifier-only link in its context.  The format of such links is
  ~denote-id-only-link-format~.

#+findex: denote-select-linked-file-prompt
+ Function ~denote-select-linked-file-prompt~ :: Prompt for linked
  file among =FILES=.

#+findex: denote-get-links
+ Function ~denote-get-links~ :: Return list of links in current or
  optional =FILE=. With optional =FILES= consider only those,
  otherwise use the return value of ~denote-directory-files~. Also see
  ~denote-get-backlinks~.

#+findex: denote-get-backlinks
+ Function ~denote-get-backlinks~ :: Return list of backlinks in
  current or optional =FILE=. Also see ~denote-get-links~.

#+findex: denote-link-description-with-signature-and-title
+ Function ~denote-link-description-with-signature-and-title~ :: Return
  link description for =FILE= with =FILE-TYPE=. For backward
  compatibility, =FILE-TYPE= is an optional parameter. If it is ~nil~,
  then compute =FILE-TYPE= internally. [ =FILE-TYPE= is added as part
  of {{{development-version}}}. ]

  - If the region is active, use it as the description.

  - If =FILE= has a signature, then format the description as a sequence
    of the signature text and the title with two spaces between them.

  - If =FILE= does not have a signature, then use its title as the
    description.

  - If none of the above works, return an empty string.

  This function is useful as the value of the user option
  ~denote-link-description-format~ (which can optionally be bound to a
  function).

** Xref interface for developers or advanced users
:PROPERTIES:
:CUSTOM_ID: h:e824c215-1c31-4b26-b994-7df67341d075
:END:

- Function ~denote-retrieve-groups-xref-query~ :: Access location of
  xrefs for =QUERY= and group them per file. Limit the search to text
  files.

- Function ~denote-retrieve-files-xref-query~ :: Return sorted,
  deduplicated file names with matches for =QUERY= in their contents.
  Limit the search to text files.

- Function ~denote-retrieve-xref-alist~ :: Return xref alist of files
  with location of matches for =QUERY=. With optional
  =FILES-MATCHING-REGEXP=, limit the list of files accordingly (per
  ~denote-directory-files~). At all times limit the search to text
  files.

** Renaming files interface for developers or advanced users
:PROPERTIES:
:CUSTOM_ID: h:66d31f42-6092-493a-97db-83b217db9d96
:END:

#+vindex: denote-rename-rewrite-front-matter
- Variable ~denote-rename-rewrite-front-matter~ :: When non-nil,
  rewrite the front matter if appropriate. The purpose of this
  variable is to be ~let~ bound to nil by a caller of the command
  ~denote-rename-file~ or related. This will have the effect of not
  rewriting the file's front matter.

#+findex: denote-rename-file-prompt
- Function ~denote-rename-file-prompt~ :: Prompt to rename file named
  =OLD-NAME= to =NEW-NAME=. If ~denote-rename-confirmations~ does not
  contain ~modify-file-name~, return t without prompting.

#+findex: denote-rename-file-and-buffer
+ Function ~denote-rename-file-and-buffer~ :: Rename file named
  =OLD-NAME= to =NEW-NAME=, updating buffer name.

#+findex: denote-prepend-front-matter
+ Function ~denote-prepend-front-matter~ :: Prepend front matter to
  =FILE=. The =TITLE=, =KEYWORDS=, =DATE=, =ID=, =SIGNATURE=, and
  =FILE-TYPE= are passed from the renaming command and are used to
  construct a new front matter block if appropriate.

#+findex: denote-rewrite-front-matter
+ Function ~denote-rewrite-front-matter~ :: Rewrite front matter of
  note after ~denote-rename-file~ (or related). The =FILE=, =TITLE=,
  =KEYWORDS=, =SIGNATURE=, =DATE=, =IDENTIFIER=, and =FILE-TYPE=
  arguments are given by the renaming command and are used to construct
  new front matter values if appropriate. If ~denote-rename-confirmations~
  contains ~rewrite-front-matter~, prompt to confirm the rewriting of
  the front matter. Otherwise produce a ~y-or-n-p~ prompt to that
  effect.

#+findex: denote-add-front-matter-prompt
+ Function ~denote-add-front-matter-prompt~ :: Prompt to add a
  front-matter to =FILE=. Return non-nil if a new front matter should
  be added. If ~denote-rename-confirmations~ does not contain
  ~add-front-matter~, return t without prompting.

#+findex: denote-rewrite-keywords
+ Function ~denote-rewrite-keywords~ :: Rewrite =KEYWORDS= in =FILE=
  outright according to =FILE-TYPE=. Do the same as
  ~denote-rewrite-front-matter~ for keywords, but do not ask for
  confirmation. With optional =SAVE-BUFFER=, save the buffer
  corresponding to =FILE=. This function is for use in the commands
  ~denote-keywords-add~, ~denote-keywords-remove~,
  ~denote-dired-rename-files~, or related.

#+findex: denote-update-dired-buffers
+ Function ~denote-update-dired-buffers~ :: Update Dired buffers of
  variable ~denote-directory~. Also revert the current Dired buffer
  even if it is not inside the ~denote-directory~. Note that the
  ~denote-directory~ accepts a directory-local value for what we
  internally refer to as "silos" ([[#h:15719799-a5ff-4e9a-9f10-4ca03ef8f6c5][Maintain separate directories for notes]]).

* Troubleshoot Denote in a pristine environment
:PROPERTIES:
:CUSTOM_ID: h:9c4467d5-6480-4681-80fb-cd9717bf8b3b
:END:

Sometimes we get reports on bugs that may not be actually caused by
some error in the Denote code base.  To help gain insight into what
the problem is, we need to be able to reproduce the issue in a minimum
viable system.  Below is one way to achieve this.

1. Find where your =denote.el= file is stored on your filesystem.

2. Assuming you have already installed the package, one way to do this
   is to invoke =M-x find-library= and search for ~denote~.  It will
   take you to the source file.  There do =M-x eval-expression=, which
   will bring up a minibuffer prompt.  At the prompt evaluate:

#+begin_example emacs-lisp
(kill-new (expand-file-name (buffer-file-name)))
#+end_example

3. The above will save the full file system path to your kill ring.

4. In a terminal emulator or an =M-x shell= buffer execute:

#+begin_example
emacs -Q
#+end_example

5. This will open a new instance of Emacs in a pristine environment.
   Only the default settings are loaded.

6. In the =*scratch*= buffer of =emacs -Q=, add your configurations
   like the following and try to reproduce the issue:

#+begin_example emacs-lisp
(require 'denote "/full/path/to/what/you/got/denote.el")

;; Your configurations here
#+end_example

Then try to see if your problem still occurs.  If it does, then the
fault is with Denote.  Otherwise there is something external to it
that we need to account for.  Whatever the case, this exercise helps
us get a better sense of the specifics.

* Contributing
:PROPERTIES:
:CUSTOM_ID: h:1ebe4865-c001-4747-a6f2-0fe45aad71cd
:END:

Denote is a GNU ELPA package. As such, any significant change to the
code requires copyright assignment to the Free Software Foundation
(more below).

You do not need to be a programmer to contribute to this package.
Sharing an idea or describing a workflow is equally helpful, as it
teaches us something we may not know and might be able to cover either
by extending Denote or expanding this manual. If you prefer to write a
blog post, make sure you share it with us: we can add a section herein
referencing all such articles. Everyone gets acknowledged
([[#h:f8126820-3b59-49fa-bcc2-73bd60132bb9][Acknowledgements]]). There is no such thing as an "insignificant
contribution"---they all matter.

+ Package name (GNU ELPA): ~denote~
+ Official manual: <https://protesilaos.com/emacs/denote>
+ Change log: <https://protesilaos.com/emacs/denote-changelog>
+ Git repositories:
  + GitHub: <https://github.com/protesilaos/denote>
  + GitLab: <https://gitlab.com/protesilaos/denote>

If our public media are not suitable, you are welcome to contact me
(Protesilaos) in private: <https://protesilaos.com/contact>.

Copyright assignment is a prerequisite to sharing code. It is a simple
process. Check the request form below (please adapt it accordingly).
You must write an email to the address mentioned in the form and then
wait for the FSF to send you a legal agreement. Sign the document and
file it back to them. This could all happen via email and take about a
week. You are encouraged to go through this process. You only need to
do it once. It will allow you to make contributions to Emacs in
general.

#+begin_example text
Please email the following information to assign@gnu.org, and we
will send you the assignment form for your past and future changes.

Please use your full legal name (in ASCII characters) as the subject
line of the message.

REQUEST: SEND FORM FOR PAST AND FUTURE CHANGES

[What is the name of the program or package you're contributing to?]

GNU Emacs

[Did you copy any files or text written by someone else in these changes?
Even if that material is free software, we need to know about it.]

Copied a few snippets from the same files I edited.  Their author,
Protesilaos Stavrou, has already assigned copyright to the Free Software
Foundation.

[Do you have an employer who might have a basis to claim to own
your changes?  Do you attend a school which might make such a claim?]


[For the copyright registration, what country are you a citizen of?]


[What year were you born?]


[Please write your email address here.]


[Please write your postal address here.]





[Which files have you changed so far, and which new files have you written
so far?]

#+end_example

** Wishlist of what we can do to extend Denote
:PROPERTIES:
:CUSTOM_ID: h:044a6a0f-e382-4013-8279-8bf4e64e73c0
:END:

These are various ideas to extend Denote. Whether they should be in
the core package or a separate extension is something we can discuss.
I, Protesilaos, am happy to help anyone who wants to do any of this.

- denote-embark.el :: Provide integration with the ~embark~ package.
  This can be for doing something with the identifier/link at point.
  For example, it could provide an action to produce backlinks for the
  identifier/file we are linking to, not just the current one.

- denote-transient.el :: The ~transient~ package is built into Emacs
  29 (Denote supports Emacs 28 though). We can use it to define an
  alternative to what we have for the menu bar. Perhaps this interface
  can used to toggle various options, such as to call ~denote~ with a
  different set of prompts.

- Encode the day in the identifier :: The idea is to use some coded
  reference for Monday, Tuesday, etc. instead of having the generic
  =T= in the identifier. For example, Monday is =A= so the identifier
  for it is something like =20240219A101522= instead of what we now
  have as =20240219T101522=. The old method should still be supported.
  Apart from changing a few regular expressions, this does not seem
  too complex to me. We would need a user option to opt in to such a
  feature. Then tweak the relevant parts. The tricky issue is to
  define a mapping of day names to letters/symbols that works for
  everyone. Do all countries have a seven-day week, for example? We
  need something universally applicable here.

Anything else? You are welcome to discuss these and/or add to the
list.

* Publications about Denote
:PROPERTIES:
:CUSTOM_ID: h:ca0c38f9-fa3e-4901-947e-1b589335781d
:END:

The Emacs community is putting Denote to great use.  This section
includes publications that show how people configure their note-taking
setup.  If you have a blog post, video, or configuration file about
Denote, feel welcome to tell us about it ([[#h:1ebe4865-c001-4747-a6f2-0fe45aad71cd][Contributing]]).

+ David Wilson (SystemCrafters): /Generating a Blog Site from Denote
  Entries/, 2022-09-09, <https://www.youtube.com/watch?v=5R7ad5xz5wo>

+ David Wilson (SystemCrafters): /Trying Out Prot's Denote, an Org
  Roam Alternative?/, 2022-07-15, <https://www.youtube.com/watch?v=QcRY_rsX0yY>

+ Jack Baty: /Keeping my Org Agenda updated based on Denote keywords/,
  2022-11-30, <https://baty.net/2022/keeping-my-org-agenda-updated>

+ Jeremy Friesen: /Denote Emacs Configuration/, 2022-10-02,
  <https://takeonrules.com/2022/10/09/denote-emacs-configuration/>

+ Jeremy Friesen: /Exploring the Denote Emacs Package/, 2022-10-01,
  <https://takeonrules.com/2022/10/01/exploring-the-denote-emacs-package/>

+ Jeremy Friesen: /Migration Plan for Org-Roam Notes to Denote/,
  2022-10-02, <https://takeonrules.com/2022/10/02/migration-plan-for-org-roam-notes-to-denote/>

+ Jeremy Friesen: /Project Dispatch Menu with Org Mode Metadata,
  Denote, and Transient/, 2022-11-19,
  <https://takeonrules.com/2022/11/19/project-dispatch-menu-with-org-mode-metadata-denote-and-transient/>

+ Mohamed Suliman: /Managing a bibliography of BiBTeX entries with
  Denote/, 2022-12-20, <https://www.scss.tcd.ie/~sulimanm/posts/denote-bibliography.html>

+ Peter Prevos: /Simulating Text Files with R to Test the Emacs Denote
  Package/, 2022-07-28, <https://lucidmanager.org/productivity/testing-denote-package/>

+ Peter Prevos: /Emacs Writing Studio/, 2023-10-19. A configuration for authors, using Denote for taking notes, literature reviews and manage collections of images:
  - <https://lucidmanager.org/productivity/taking-notes-with-emacs-denote/>
  - <https://lucidmanager.org/productivity/denote-explore/>
  - <https://lucidmanager.org/productivity/bibliographic-notes-in-emacs-with-citar-denote/>
  - <https://lucidmanager.org/productivity/using-emacs-image-dired/>

+ Stefan Thesing: /Denote as a Zettelkasten/, 2023-03-02,
  <https://www.thesing-online.de/blog/denote-as-a-zettelkasten>

+ Summer Emacs: /An explanation of how I use Emacs/, 2023-05-04,
  <https://github.com/summeremacs/howiuseemacs/blob/main/full-explanation-of-how-i-use-emacs.org>

* Alternatives to Denote
:PROPERTIES:
:CUSTOM_ID: h:dbb51a1b-90b8-48e8-953c-e2fb3e36981e
:END:

What follows is a list of Emacs packages for note-taking.  I
(Protesilaos) have not used any of them, as I was manually applying my
file-naming scheme beforehand and by the time those packages were
available I was already hacking on the predecessor of Denote as a means
of learning Emacs Lisp (a package which I called "Unassuming Sidenotes
of Little Significance", aka "USLS" which is pronounced as "U-S-L-S" or
"useless").  As such, I cannot comment at length on the differences
between Denote and each of those packages, beside what I gather from
their documentation.

+ [[https://github.com/org-roam/org-roam][org-roam]] :: The de facto standard in the Emacs milieu---and rightly
  so!  It has a massive community, is featureful, and should be an
  excellent companion to anyone who is invested in the Org ecosystem
  and/or knows what "Roam" is (I don't).  It has been explained to me
  that Org Roam uses a database to store a cache about your notes.  It
  otherwise uses standard Org files.  The cache helps refer to the same
  node through aliases which can provide lots of options.  Personally, I
  follow a single-topic-per-note approach, so anything beyond that is
  overkill.  If the database is only for a cache, then maybe that has no
  downside, though I am careful with any kind of specialised program as
  it creates a dependency.  If you ask me about database software in
  particular, I have no idea how to use one, let alone debug it or
  retrieve data from it if something goes awry (I could learn, but that
  is beside the point).

+ [[https://github.com/localauthor/zk][zk (or zk.el)]] :: Reading its documentation makes me think that this is
  Denote's sibling---the two projects have a lot of things in common,
  including the preference to rely on plain files and standard tools.
  The core difference is that Denote has a strict file-naming scheme.
  Other differences in available features are, in principle, matters of
  style or circumstance: both packages can have them.  As its initials
  imply, ZK enables a zettelkasten-like workflow.  It does not enforce
  it though, letting the user adapt the method to their needs and
  requirements.

+ [[https://github.com/ymherklotz/emacs-zettelkasten][zettelkasten]] :: This is another one of Denote's relatives, at least
  insofar as the goal of simplicity is concerned.  The major difference
  is that according to its documentation "the name of the file that is
  created is just a unique ID".  This is not consistent with our
  file-naming scheme which is all about making sense of your files by
  their name alone and being able to visually parse a listing of them
  without any kind of specialised tool (e.g. =ls -l= or =ls -C= on the
  command-line from inside the ~denote-directory~ give you a
  human-readable set of files names, while =find * -maxdepth 0 -type f=
  is another approach).

+ [[https://github.com/EFLS/zetteldeft][zetteldeft]] :: This is a zettelkasten note-taking system built on top
  of the =deft= package.  Deft provides a search interface to a
  directory, in this case the one holding the user's =zetteldeft= notes.
  Denote has no such dependency and is not opinionated about how the
  user prefers to search/access their notes: use Dired, Grep, the
  =consult= package, or whatever else you already have set up for all
  things Emacs, not just your notes.

Searching through =M-x list-packages= for "zettel" brings up more
matches.  =zetteldesk= is an extension to Org Roam and, as such, I
cannot possibly know what Org Roam truly misses and what the added-value
of this package is.  =neuron-mode= builds on top of an external program
called =neuron=, which I have never used.

Searching for "note" gives us a few more results.  =notes-mode= has
precious little documentation and I cannot tell what it actually does
(as I said in my presentation for LibrePlanet 2022, inadequate docs are
a bug).  =side-notes= differs from what we try to do with Denote, as it
basically gives you the means to record your thoughts about some other
project you are working on and keep them on the side: so it and Denote
should not be mutually exclusive.

If I missed something, please let me know.

** Alternative implementations and further reading
:PROPERTIES:
:CUSTOM_ID: h:188c0986-f2fa-444f-b493-5429356e75cf
:END:

This section covers blog posts and implementations from the Emacs
community about the topic of note-taking and file organization.  They
may refer to some of the packages covered in the previous section or
provide their custom code ([[#h:dbb51a1b-90b8-48e8-953c-e2fb3e36981e][Alternatives to Denote]]).  The list is
unsorted.

+ José Antonio Ortega Ruiz (aka "jao") explains a note-taking method
  that is simple like Denote but differs in other ways.  An interesting
  approach overall: https://jao.io/blog/simple-note-taking.html.

+ Jethro Kuan (the main =org-roam= developer) explains their note-taking
  techniques: https://jethrokuan.github.io/org-roam-guide/.  Good ideas
  all round, regardless of the package/code you choose to use.

+ Karl Voit's tools [[https://github.com/novoid/date2name][date2name]], [[https://github.com/novoid/filetags/][filetags]], [[https://github.com/novoid/appendfilename/][appendfilename]], and
  [[https://github.com/novoid/move2archive][move2archive]] provide a Python-based implementation to organize
  individual files which do not require Emacs.  His approach ([[https://karl-voit.at/managing-digital-photographs/][blog
  post]] and his [[https://www.youtube.com/watch?v=rckSVmYCH90][presentation at GLT18]]) has been complemented by [[https://github.com/novoid/memacs][memacs]]
  to process e.g., the date of creation of photographs, or the log of
  a phone call in a format compatible to org.

[ Development note: help expand this list. ]

* Frequently Asked Questions
:PROPERTIES:
:CUSTOM_ID: h:da2944c6-cde6-4c65-8f2d-579305a159bb
:END:

I (Protesilaos) answer some questions I have received or might get.  It
is assumed that you have read the rest of this manual: I will not go
into the specifics of how Denote works.

** Why develop Denote when PACKAGE already exists?
:PROPERTIES:
:CUSTOM_ID: h:b875450a-ae22-4899-ac23-c10fa9c279bb
:END:

I wrote Denote because I was using a variant of Denote's file-naming
scheme before I was even an Emacs user (I switched to Emacs from
Tmux+Vim+CLI in the summer of 2019).  I was originally inspired by
Jekyll, the static site generator, which I started using for my website
in 2016 (was on WordPress before).  Jekyll's files follow the
=YYYY-MM-DD-TITLE.md= pattern.  I liked its efficiency relative to the
unstructured mess I had before.  Eventually, I started using that scheme
outside the confines of my website's source code.  Over time I refined
it and here we are.

Note-taking is something I take very seriously, as I am a prolific
writer (just check my website, which only reveals the tip of the
iceberg).  As such, I need a program that does exactly what I want and
which I know how to extend.  I originally tried to use Org capture
templates to create new files with a Denote-style file-naming scheme but
never managed to achieve it.  Maybe because ~org-capture~ has some
hard-coded assumptions or I simply am not competent enough to hack on
core Org facilities.  Whatever the case, an alternative was in order.

The existence of PACKAGE is never a good reason for me not to conduct my
own experiments for recreational, educational, or practical purposes.
When the question arises of "why not contribute to PACKAGE instead?" the
answer is that without me experimenting in the first place, I would lack
the skills for such a task.  Furthermore, contributing to another
package does not guarantee I get what I want in terms of workflow.

Whether you should use Denote or not is another matter altogether:
choose whatever you want.

** Why not rely exclusively on Org?
:PROPERTIES:
:CUSTOM_ID: h:b9831849-5c71-484e-b444-bac19cc13151
:END:

I think Org is one of Emacs' killer apps.  I also believe it is not the
right tool for every job.  When I write notes, I want to focus on
writing.  Nothing more.  I thus have no need for stuff like org-babel,
scheduling to-do items, clocking time, and so on.  The more "mental
dependencies" you add to your workflow, the heavier the burden you carry
and the less focused you are on the task at hand: there is always that
temptation to tweak the markup, tinker with some syntactic construct,
obsess about what ought to be irrelevant to writing as such.

In technical terms, I also am not fond of Org's code base (I understand
why it is the way it is---just commenting on the fact).  Ever tried to
read it?  You will routinely find functions that are tens-to-hundreds of
lines long and have all sorts of special casing.  As I am not a
programmer and only learnt to write Elisp through trial and error, I
have no confidence in my ability to make Org do what I want at that
level, hence =denote= instead of =org-denote= or something.

Perhaps the master programmer is one who can deal with complexity and
keep adding to it.  I am of the opposite view, as language---code
included---is at its communicative best when it is clear and accessible.

Make no mistake: I use Org for the agenda and also to write technical
documentation that needs to be exported to various formats, including
this very manual.

** Why care about Unix tools when you use Emacs?
:PROPERTIES:
:CUSTOM_ID: h:da1e2469-8f04-450b-a379-a854efa80a36
:END:

My notes form part of my longer-term storage.  I do not want to have to
rely on a special program to be able to read them or filter them.  Unix
is universal, at least as far as I am concerned.

Denote streamlines some tasks and makes things easier in general, which
is consistent with how Emacs provides a layer of interactivity on top of
Unix.  Still, Denote's utilities can, in principle, be implemented as
POSIX shell scripts (minus the Emacs-specific parts like fontification
in Dired or the buttonization of links).

Portability matters.  For example, in the future I might own a
smartphone, so I prefer not to require Emacs, Org, or some other
executable to access my files on the go.

Furthermore, I might want to share those files with someone.  If I make
Emacs a requirement, I am limiting my circle to a handful of relatively
advanced users.

Please don't misinterpret this: I am using Emacs full-time for my
computing and maintain a growing list of packages for it.  This is just
me thinking long-term.

** Why many small files instead of few large ones?
:PROPERTIES:
:CUSTOM_ID: h:7d2e7b8a-d484-4c1d-8688-17f70f242ad7
:END:

I have read that Org favours the latter method.  If true, I strongly
disagree with it because of the implicit dependency it introduces and
the way it favours machine-friendliness over human-readability in terms
of accessing information.  Notes are long-term storage.  I might want to
access them on (i) some device with limited features, (ii) print on
paper, (iii) share with another person who is not a tech wizard.

There are good arguments for few large files, but all either prioritize
machine-friendliness or presuppose the use of sophisticated tools like
Emacs+Org.

Good luck using =less= on a generic TTY to read a file with a zillion
words, headings, sub-headings, sub-sub-headings, property drawers, and
other constructs!  You will not get the otherwise wonderful folding of
headings the way you do in Emacs---do not take such features for
granted.

My point is that notes should be atomic to help the user---and
potentially the user's family, friends, acquaintances---make sense of
them in a wide range of scenaria.  The more program-agnostic your file
is, the better for you and/or everyone else you might share your
writings with.

Human-readability means that we optimize for what matters to us.  If (a)
you are the only one who will ever read your notes, (b) always have
access to good software like Emacs+Org, (c) do not care about printing
on paper, then Denote's model is not for you.  Maybe you need to tweak
some ~org-capture~ template to append a new entry to one mega file (I do
that for my Org agenda, by the way, as I explained before about using
the right tool for the job).

** Does Denote perform well at scale?
:PROPERTIES:
:CUSTOM_ID: h:863f812a-aac7-42ea-83b3-fbbdb58e08d7
:END:

Denote does not do anything fancy and has no special requirements: it
uses standard tools to accomplish ordinary tasks.  If Emacs can cope
with lots of files, then that is all you need to know: Denote will work.

To put this to the test, Peter Prevos is running simulations with R that
generate large volumes of notes.  You can read the technicalities here:
<https://lucidmanager.org/productivity/testing-denote-package/>.
Excerpt:

#+begin_quote
Using this code I generated ten thousands notes and used this to test
the Denote package to see it if works at a large scale. This tests shows
that Prot's approach is perfectly capable of working with thousands of
notes.
#+end_quote

Of course, we are always prepared to make refinements to the code, where
necessary, without compromising on the project's principles.

** I add TODOs to my notes; will many files slow down the Org agenda?
:PROPERTIES:
:CUSTOM_ID: h:63c2f8d4-79ed-4c55-b3ef-e048a05802c0
:END:

Yes, many files will slow down the agenda due to how that works.  Org
collects all files specified in the ~org-agenda-files~, searches through
their contents for timestamped entries, and then loops through all days
to determine where each entry belongs.  The more days and more files,
the longer it takes to build the agenda.  Doing this with potentially
hundreds of files will have a noticeable impact on performance.

This is not a deficiency of Denote.  It happens with generic Org files.
The way the agenda is built is heavily favoring the use of a single file
that holds all your timestamped entries (or at least a few such files).
Tens or hundreds of files are inefficient for this job.  Plus doing so
has the side-effect of making Emacs open all those files, which you
probably do not need.

If you want my opinion though, be more forceful with the separation of
concerns.  Decouple your knowledge base from your ephemeral to-do list:
Denote (and others) can be used for the former, while you let standard
Org work splendidly for the latter---that is what I do, anyway.

Org has a powerful linking facility, whether you use ~org-store-link~ or
do it via an ~org-capture~ template.  If you want a certain note to be
associated with a task, just store the task in a single =tasks.org= (or
however you name it) and link to the relevant context.

Do not mix your knowledge base with your to-do items.  If you need help
figuring out the specifics of this workflow, you are welcome to ask for
help in our relevant channels ([[#h:1ebe4865-c001-4747-a6f2-0fe45aad71cd][Contributing]]).

** I want to sort by last modified in Dired, why won't Denote let me?
:PROPERTIES:
:CUSTOM_ID: h:a7fd5e0a-78f7-434e-aa2e-e150479c16e2
:END:

Denote does not control how Dired sorts files. I encourage you to read
the manpage of the =ls= executable. It will help you in general, while
it applies to Emacs as well via Dired. The gist is that you can update
the =ls= flags that Dired uses on-the-fly: type =C-u M-x
dired-sort-toggle-or-edit= (=C-u s= by default) and append
=--sort=time= at the prompt. To reverse the order, add the =-r= flag.
The user option ~dired-listing-switches~ sets your default preference.

For an on-demand sorted and filtered Dired listing of Denote files,
use the command ~denote-sort-dired~ ([[#h:9fe01e63-f34f-4479-8713-f162a5ca865e][Sort files by component]]).

** How do you handle the last modified case?
:PROPERTIES:
:CUSTOM_ID: h:764b5e87-cd22-4937-b5fc-af3892d6b3d8
:END:

Denote does not insert any meta data or heading pertaining to edits in
the file.  I am of the view that these either do not scale well or are
not descriptive enough.  Suppose you use a "lastmod" heading with a
timestamp: which lines where edited and what did the change amount to?

This is where an external program can be helpful.  Use a Version Control
System, such as Git, to keep track of all your notes.  Every time you
add a new file, record the addition.  Same for post-creation edits.
Your VCS will let you review the history of those changes.  For
instance, Emacs' built-in version control framework has a command that
produces a log of changes for the current file: =M-x vc-print-log=,
bound to =C-x v l= by default.  From there one can access the
corresponding diff output (use =M-x describe-mode= (=C-h m=) in an
unfamiliar buffer to learn more about it).  With Git in particular,
Emacs users have the option of the all-round excellent =magit= package.

In short: let Denote (or equivalent) create notes and link between them,
the file manager organise and provide access to files, search programs
deal with searching and narrowing, and version control software handle
the tracking of changes.

** Why are some Org links opening outside Emacs?
:PROPERTIES:
:CUSTOM_ID: h:4f354db1-aa78-47fd-ac60-c3d1e0f0b0a4
:END:

Org has its own mechanism to determine how best to open a link. This
affects the =file:= link type, but also the =denote:= one (which is
designed to be as close to =file:= as possible).

When following a link, Org usually displays the data in an Emacs
buffer, though it might launch an external application instead. The
idea is to use a specialised program when that is relevant, such as to
display a video. Though there can be scenaria the user does not like,
such as when Org decides to load =.md= or =.html= files with an
external app. To compound the problem, users can name any file type
using the Denote file-naming scheme, including images, PDFs, videos,
and more ([[#h:532e8e2a-9b7d-41c0-8f4b-3c5cbb7d4dca][Renaming files]]).

To instruct Org to stay in Emacs for such cases, the user needs to
modify the variable ~org-file-apps~, which is not specific to Denote.
As one use-case, ~org-file-apps~ associates a regular expression to
match file names with a method on how to display them (do =M-x
describe-variable= and then search for ~org-file-apps~ to read its
documentation). Thus, the user can use something like the following
in their Org or Denote configuration:

#+begin_src emacs-lisp
;; Tell Org to use Emacs when opening files that end in .md
(add-to-list 'org-file-apps '("\\.md\\'" . emacs))

;; Do the same for .html
(add-to-list 'org-file-apps '("\\.html\\'" . emacs))
#+end_src

Each of these adds a new entry to the existing value of that user
option. Replace =md= or =html= with the desired file type extension.

** Speed up backlinks' or query links' buffer creation?
:PROPERTIES:
:CUSTOM_ID: h:893eec49-d7be-4603-bcff-fcc247244011
:END:

Denote leverages the built-in =xref= library to search for the
identifier of the current file and return any links to it.  For users
of Emacs version 28 or higher, there exists a user option to specify
the program that performs this search: ~xref-search-program~.  The
default is =grep=, which can be slow, though one may opt for =ugrep=,
=ripgrep=, or even specify something else (read the doc string of that
user option for the details).

Try either for these for better results:

#+begin_src emacs-lisp
(setq xref-search-program 'ripgrep)

;; OR

(setq xref-search-program 'ugrep)
#+end_src

To use whatever executable is available on your system, use something
like this:

#+begin_src emacs-lisp
;; Prefer ripgrep, then ugrep, and fall back to regular grep.
(setq xref-search-program
      (cond
       ((or (executable-find "ripgrep")
            (executable-find "rg"))
        'ripgrep)
       ((executable-find "ugrep")
        'ugrep)
       (t
        'grep)))
#+end_src

** Why do I get "Search failed with status 1" when I search for backlinks?
:PROPERTIES:
:CUSTOM_ID: h:42f6b07e-5956-469a-8294-17f9cf62eb2b
:END:

Denote uses [[info:emacs#Xref][Emacs' Xref]] to find backlinks.  Xref requires ~xargs~ and
one of ~grep~ or ~ripgrep~, depending on your configuration.

This is usually not an issue on *nix systems, but the necessary
executables are not available on Windows Emacs distributions.  Please
ensure that you have both ~xargs~ and either ~grep~ or ~ripgrep~
available within your ~PATH~ environment variable.

If you have ~git~ on Windows installed, then you may use the following
code (adjust the git's installation path if necessary):
#+begin_src emacs-lisp
  (setenv "PATH" (concat (getenv "PATH") ";" "C:\\Program Files\\Git\\usr\\bin"))
#+end_src

** Why do I get a double =#+title= in Doom Emacs?
:PROPERTIES:
:CUSTOM_ID: h:0f737b7d-40e6-46a7-b1db-117c0ffcbfef
:END:

Doom Emacs provides a set of bespoke templates for Org. One of those
prefills any new Org file with a =#+title= field. So when Denote
creates a new Org file and inserts front matter to it, it inevitably
adds an extra title to the existing one.

This is not a Denote problem. We can only expect a new file to be
empty by default. Check how to disable the relevant module in your
Doom Emacs configuration file.

* Acknowledgements
:PROPERTIES:
:CUSTOM_ID: h:f8126820-3b59-49fa-bcc2-73bd60132bb9
:END:
#+cindex: Contributors

Denote is meant to be a collective effort.  Every bit of help matters.

+ Author/maintainer :: Protesilaos Stavrou.

+ Contributions to code or the manual :: Abdul-Lateef Haji-Ali, Abin
  Simon, Adam Růžička, Alan Schmitt, Alexandre Rousseau, Ashish
  Panigrahi, Ashton Wiersdorf, Aziz, Benjamin Kästner, Bruno Boal,
  Charanjit Singh, Claudio Migliorelli, Clemens Radermacher, Colin
  McLear, Damien Cassou, Eduardo Grajeda, Elias Storms, Eshel Yaron,
  Florian, Glenna D., Graham Marlow, Hilde Rhyne, Ivan Sokolov, Jack
  Baty, Jakub Szczerbowski, James Kalyan, Jean-Charles Bagneris,
  Jean-Philippe Gagné Guay, Jianwei Hou, Joseph Turner, Jürgen Hötzel,
  Kaushal Modi, Kai von Fintel, Kierin Bell, Kostas Andreadis,
  Kristoffer Balintona, Kyle Meyer, Laurent Gatto, Lucas Quintana,
  Maikol Solis, Marc Fargas, Matthew Lemon, Noboru Ota (nobiot),
  Norwid Behrnd, Octavian, Peter Prevos, Philip Kaludercic, Ryota,
  Quiliro Ordóñez, Stephen R. Kifer, Stefan Monnier, Stefan Thesing,
  Thibaut Benjamin, Tomasz Hołubowicz, TomoeMami , Vedang Manerikar,
  Wesley Harvey, Yann Dutrieux, Zhenxu Xu, arsaber101, bryanrinders,
  eum3l, experimental-code-86, ezchi, jarofromel, leinfink (Henrik),
  l-o-l-h (Lincoln), mattyonweb, maxbrieiev, mentalisttraceur,
  pmenair, relict007, skissue.

+ Ideas and/or user feedback :: Abin Simon, Aditya Yadav, Alan
  Schmitt, Aleksandr Vityazev, Alex Griffin, Alex Hirschfeld, Alexis
  Purslane, Alfredo Borrás, Alp Eren Kose, André Bering, Ashton
  Wiersdorf, Bhargav Kulkarni, Benjamin Kästner, Claudio Migliorelli,
  Claudiu Tănăselia, Colin McLear, Cosmin-Octavian C, Damien Cassou,
  Elias Storms, Federico Stilman, Florian, Frédéric Willem Frank
  Ehmsen, Glenna D., Guo Yong, Hanspeter Gisler Harold Ollivier,
  IceAsteroid, Jack Baty, Jay Rajput, Jean-Charles Bagneris, Jeff
  Valk, Jens Östlund, Jeremy Friesen, Jonathan Sahar, Johan Bolmsjö,
  Jonas Großekathöfer, Jousimies, Juanjo Presa, Julian Hoch, Kai von
  Fintel, Kaushal Modi, Kolmas, Lukas C. Bossert, M. Hadi Timachi,
  Maikol Solis, Mark Olson, Mirko Hernandez, Morten Kjeldgaard, Niall
  Dooley, Nick Bell, Oliver Epper, Paul van Gelder, Peter Prevos,
  Peter Smith, Riccardo Giannitrapani, Rory Molinari, Samuel W. Flint,
  Sergio Rey, Suhail Singh, Shreyas Ragavan, Stefan Thesing, Summer
  Emacs, Sven Seebeck, Taoufik, TJ Stankus, Vick (VicZz), Viktor Haag,
  Vineet C. Kulkarni, Wade Mealing, Wilf, Yi Liu, Ypot, atanasj,
  azegas, babusri, bdillahu, coherentstate, doolio, duli, drcxd,
  elge70, elliottw, fingerknight, hpgisler, hyperfocus1337,johkneisl,
  jtpavlock, juh, leafarbelm, mentalisttraceur, mjkalyan, oatmealm,
  pRot0ta1p, rbenit68, relict007, sarcom-sar, sienic, skissue, sundar
  bp, wuzhihao, yetanotherfossman, zadca123

Special thanks to Peter Povinec who helped refine the file-naming
scheme, which is the cornerstone of this project.

Special thanks to Jean-Philippe Gagné Guay for the numerous
contributions to the code base.

* GNU Free Documentation License
:PROPERTIES:
:APPENDIX: t
:CUSTOM_ID: h:2d84e73e-c143-43b5-b388-a6765da974ea
:END:

#+texinfo: @include doclicense.texi

#+begin_export html
<pre>

                GNU Free Documentation License
                 Version 1.3, 3 November 2008


 Copyright (C) 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc.
     <https://fsf.org/>
 Everyone is permitted to copy and distribute verbatim copies
 of this license document, but changing it is not allowed.

0. PREAMBLE

The purpose of this License is to make a manual, textbook, or other
functional and useful document "free" in the sense of freedom: to
assure everyone the effective freedom to copy and redistribute it,
with or without modifying it, either commercially or noncommercially.
Secondarily, this License preserves for the author and publisher a way
to get credit for their work, while not being considered responsible
for modifications made by others.

This License is a kind of "copyleft", which means that derivative
works of the document must themselves be free in the same sense.  It
complements the GNU General Public License, which is a copyleft
license designed for free software.

We have designed this License in order to use it for manuals for free
software, because free software needs free documentation: a free
program should come with manuals providing the same freedoms that the
software does.  But this License is not limited to software manuals;
it can be used for any textual work, regardless of subject matter or
whether it is published as a printed book.  We recommend this License
principally for works whose purpose is instruction or reference.


1. APPLICABILITY AND DEFINITIONS

This License applies to any manual or other work, in any medium, that
contains a notice placed by the copyright holder saying it can be
distributed under the terms of this License.  Such a notice grants a
world-wide, royalty-free license, unlimited in duration, to use that
work under the conditions stated herein.  The "Document", below,
refers to any such manual or work.  Any member of the public is a
licensee, and is addressed as "you".  You accept the license if you
copy, modify or distribute the work in a way requiring permission
under copyright law.

A "Modified Version" of the Document means any work containing the
Document or a portion of it, either copied verbatim, or with
modifications and/or translated into another language.

A "Secondary Section" is a named appendix or a front-matter section of
the Document that deals exclusively with the relationship of the
publishers or authors of the Document to the Document's overall
subject (or to related matters) and contains nothing that could fall
directly within that overall subject.  (Thus, if the Document is in
part a textbook of mathematics, a Secondary Section may not explain
any mathematics.)  The relationship could be a matter of historical
connection with the subject or with related matters, or of legal,
commercial, philosophical, ethical or political position regarding
them.

The "Invariant Sections" are certain Secondary Sections whose titles
are designated, as being those of Invariant Sections, in the notice
that says that the Document is released under this License.  If a
section does not fit the above definition of Secondary then it is not
allowed to be designated as Invariant.  The Document may contain zero
Invariant Sections.  If the Document does not identify any Invariant
Sections then there are none.

The "Cover Texts" are certain short passages of text that are listed,
as Front-Cover Texts or Back-Cover Texts, in the notice that says that
the Document is released under this License.  A Front-Cover Text may
be at most 5 words, and a Back-Cover Text may be at most 25 words.

A "Transparent" copy of the Document means a machine-readable copy,
represented in a format whose specification is available to the
general public, that is suitable for revising the document
straightforwardly with generic text editors or (for images composed of
pixels) generic paint programs or (for drawings) some widely available
drawing editor, and that is suitable for input to text formatters or
for automatic translation to a variety of formats suitable for input
to text formatters.  A copy made in an otherwise Transparent file
format whose markup, or absence of markup, has been arranged to thwart
or discourage subsequent modification by readers is not Transparent.
An image format is not Transparent if used for any substantial amount
of text.  A copy that is not "Transparent" is called "Opaque".

Examples of suitable formats for Transparent copies include plain
ASCII without markup, Texinfo input format, LaTeX input format, SGML
or XML using a publicly available DTD, and standard-conforming simple
HTML, PostScript or PDF designed for human modification.  Examples of
transparent image formats include PNG, XCF and JPG.  Opaque formats
include proprietary formats that can be read and edited only by
proprietary word processors, SGML or XML for which the DTD and/or
processing tools are not generally available, and the
machine-generated HTML, PostScript or PDF produced by some word
processors for output purposes only.

The "Title Page" means, for a printed book, the title page itself,
plus such following pages as are needed to hold, legibly, the material
this License requires to appear in the title page.  For works in
formats which do not have any title page as such, "Title Page" means
the text near the most prominent appearance of the work's title,
preceding the beginning of the body of the text.

The "publisher" means any person or entity that distributes copies of
the Document to the public.

A section "Entitled XYZ" means a named subunit of the Document whose
title either is precisely XYZ or contains XYZ in parentheses following
text that translates XYZ in another language.  (Here XYZ stands for a
specific section name mentioned below, such as "Acknowledgements",
"Dedications", "Endorsements", or "History".)  To "Preserve the Title"
of such a section when you modify the Document means that it remains a
section "Entitled XYZ" according to this definition.

The Document may include Warranty Disclaimers next to the notice which
states that this License applies to the Document.  These Warranty
Disclaimers are considered to be included by reference in this
License, but only as regards disclaiming warranties: any other
implication that these Warranty Disclaimers may have is void and has
no effect on the meaning of this License.

2. VERBATIM COPYING

You may copy and distribute the Document in any medium, either
commercially or noncommercially, provided that this License, the
copyright notices, and the license notice saying this License applies
to the Document are reproduced in all copies, and that you add no
other conditions whatsoever to those of this License.  You may not use
technical measures to obstruct or control the reading or further
copying of the copies you make or distribute.  However, you may accept
compensation in exchange for copies.  If you distribute a large enough
number of copies you must also follow the conditions in section 3.

You may also lend copies, under the same conditions stated above, and
you may publicly display copies.


3. COPYING IN QUANTITY

If you publish printed copies (or copies in media that commonly have
printed covers) of the Document, numbering more than 100, and the
Document's license notice requires Cover Texts, you must enclose the
copies in covers that carry, clearly and legibly, all these Cover
Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on
the back cover.  Both covers must also clearly and legibly identify
you as the publisher of these copies.  The front cover must present
the full title with all words of the title equally prominent and
visible.  You may add other material on the covers in addition.
Copying with changes limited to the covers, as long as they preserve
the title of the Document and satisfy these conditions, can be treated
as verbatim copying in other respects.

If the required texts for either cover are too voluminous to fit
legibly, you should put the first ones listed (as many as fit
reasonably) on the actual cover, and continue the rest onto adjacent
pages.

If you publish or distribute Opaque copies of the Document numbering
more than 100, you must either include a machine-readable Transparent
copy along with each Opaque copy, or state in or with each Opaque copy
a computer-network location from which the general network-using
public has access to download using public-standard network protocols
a complete Transparent copy of the Document, free of added material.
If you use the latter option, you must take reasonably prudent steps,
when you begin distribution of Opaque copies in quantity, to ensure
that this Transparent copy will remain thus accessible at the stated
location until at least one year after the last time you distribute an
Opaque copy (directly or through your agents or retailers) of that
edition to the public.

It is requested, but not required, that you contact the authors of the
Document well before redistributing any large number of copies, to
give them a chance to provide you with an updated version of the
Document.


4. MODIFICATIONS

You may copy and distribute a Modified Version of the Document under
the conditions of sections 2 and 3 above, provided that you release
the Modified Version under precisely this License, with the Modified
Version filling the role of the Document, thus licensing distribution
and modification of the Modified Version to whoever possesses a copy
of it.  In addition, you must do these things in the Modified Version:

A. Use in the Title Page (and on the covers, if any) a title distinct
   from that of the Document, and from those of previous versions
   (which should, if there were any, be listed in the History section
   of the Document).  You may use the same title as a previous version
   if the original publisher of that version gives permission.
B. List on the Title Page, as authors, one or more persons or entities
   responsible for authorship of the modifications in the Modified
   Version, together with at least five of the principal authors of the
   Document (all of its principal authors, if it has fewer than five),
   unless they release you from this requirement.
C. State on the Title page the name of the publisher of the
   Modified Version, as the publisher.
D. Preserve all the copyright notices of the Document.
E. Add an appropriate copyright notice for your modifications
   adjacent to the other copyright notices.
F. Include, immediately after the copyright notices, a license notice
   giving the public permission to use the Modified Version under the
   terms of this License, in the form shown in the Addendum below.
G. Preserve in that license notice the full lists of Invariant Sections
   and required Cover Texts given in the Document's license notice.
H. Include an unaltered copy of this License.
I. Preserve the section Entitled "History", Preserve its Title, and add
   to it an item stating at least the title, year, new authors, and
   publisher of the Modified Version as given on the Title Page.  If
   there is no section Entitled "History" in the Document, create one
   stating the title, year, authors, and publisher of the Document as
   given on its Title Page, then add an item describing the Modified
   Version as stated in the previous sentence.
J. Preserve the network location, if any, given in the Document for
   public access to a Transparent copy of the Document, and likewise
   the network locations given in the Document for previous versions
   it was based on.  These may be placed in the "History" section.
   You may omit a network location for a work that was published at
   least four years before the Document itself, or if the original
   publisher of the version it refers to gives permission.
K. For any section Entitled "Acknowledgements" or "Dedications",
   Preserve the Title of the section, and preserve in the section all
   the substance and tone of each of the contributor acknowledgements
   and/or dedications given therein.
L. Preserve all the Invariant Sections of the Document,
   unaltered in their text and in their titles.  Section numbers
   or the equivalent are not considered part of the section titles.
M. Delete any section Entitled "Endorsements".  Such a section
   may not be included in the Modified Version.
N. Do not retitle any existing section to be Entitled "Endorsements"
   or to conflict in title with any Invariant Section.
O. Preserve any Warranty Disclaimers.

If the Modified Version includes new front-matter sections or
appendices that qualify as Secondary Sections and contain no material
copied from the Document, you may at your option designate some or all
of these sections as invariant.  To do this, add their titles to the
list of Invariant Sections in the Modified Version's license notice.
These titles must be distinct from any other section titles.

You may add a section Entitled "Endorsements", provided it contains
nothing but endorsements of your Modified Version by various
parties--for example, statements of peer review or that the text has
been approved by an organization as the authoritative definition of a
standard.

You may add a passage of up to five words as a Front-Cover Text, and a
passage of up to 25 words as a Back-Cover Text, to the end of the list
of Cover Texts in the Modified Version.  Only one passage of
Front-Cover Text and one of Back-Cover Text may be added by (or
through arrangements made by) any one entity.  If the Document already
includes a cover text for the same cover, previously added by you or
by arrangement made by the same entity you are acting on behalf of,
you may not add another; but you may replace the old one, on explicit
permission from the previous publisher that added the old one.

The author(s) and publisher(s) of the Document do not by this License
give permission to use their names for publicity for or to assert or
imply endorsement of any Modified Version.


5. COMBINING DOCUMENTS

You may combine the Document with other documents released under this
License, under the terms defined in section 4 above for modified
versions, provided that you include in the combination all of the
Invariant Sections of all of the original documents, unmodified, and
list them all as Invariant Sections of your combined work in its
license notice, and that you preserve all their Warranty Disclaimers.

The combined work need only contain one copy of this License, and
multiple identical Invariant Sections may be replaced with a single
copy.  If there are multiple Invariant Sections with the same name but
different contents, make the title of each such section unique by
adding at the end of it, in parentheses, the name of the original
author or publisher of that section if known, or else a unique number.
Make the same adjustment to the section titles in the list of
Invariant Sections in the license notice of the combined work.

In the combination, you must combine any sections Entitled "History"
in the various original documents, forming one section Entitled
"History"; likewise combine any sections Entitled "Acknowledgements",
and any sections Entitled "Dedications".  You must delete all sections
Entitled "Endorsements".


6. COLLECTIONS OF DOCUMENTS

You may make a collection consisting of the Document and other
documents released under this License, and replace the individual
copies of this License in the various documents with a single copy
that is included in the collection, provided that you follow the rules
of this License for verbatim copying of each of the documents in all
other respects.

You may extract a single document from such a collection, and
distribute it individually under this License, provided you insert a
copy of this License into the extracted document, and follow this
License in all other respects regarding verbatim copying of that
document.


7. AGGREGATION WITH INDEPENDENT WORKS

A compilation of the Document or its derivatives with other separate
and independent documents or works, in or on a volume of a storage or
distribution medium, is called an "aggregate" if the copyright
resulting from the compilation is not used to limit the legal rights
of the compilation's users beyond what the individual works permit.
When the Document is included in an aggregate, this License does not
apply to the other works in the aggregate which are not themselves
derivative works of the Document.

If the Cover Text requirement of section 3 is applicable to these
copies of the Document, then if the Document is less than one half of
the entire aggregate, the Document's Cover Texts may be placed on
covers that bracket the Document within the aggregate, or the
electronic equivalent of covers if the Document is in electronic form.
Otherwise they must appear on printed covers that bracket the whole
aggregate.


8. TRANSLATION

Translation is considered a kind of modification, so you may
distribute translations of the Document under the terms of section 4.
Replacing Invariant Sections with translations requires special
permission from their copyright holders, but you may include
translations of some or all Invariant Sections in addition to the
original versions of these Invariant Sections.  You may include a
translation of this License, and all the license notices in the
Document, and any Warranty Disclaimers, provided that you also include
the original English version of this License and the original versions
of those notices and disclaimers.  In case of a disagreement between
the translation and the original version of this License or a notice
or disclaimer, the original version will prevail.

If a section in the Document is Entitled "Acknowledgements",
"Dedications", or "History", the requirement (section 4) to Preserve
its Title (section 1) will typically require changing the actual
title.


9. TERMINATION

You may not copy, modify, sublicense, or distribute the Document
except as expressly provided under this License.  Any attempt
otherwise to copy, modify, sublicense, or distribute it is void, and
will automatically terminate your rights under this License.

However, if you cease all violation of this License, then your license
from a particular copyright holder is reinstated (a) provisionally,
unless and until the copyright holder explicitly and finally
terminates your license, and (b) permanently, if the copyright holder
fails to notify you of the violation by some reasonable means prior to
60 days after the cessation.

Moreover, your license from a particular copyright holder is
reinstated permanently if the copyright holder notifies you of the
violation by some reasonable means, this is the first time you have
received notice of violation of this License (for any work) from that
copyright holder, and you cure the violation prior to 30 days after
your receipt of the notice.

Termination of your rights under this section does not terminate the
licenses of parties who have received copies or rights from you under
this License.  If your rights have been terminated and not permanently
reinstated, receipt of a copy of some or all of the same material does
not give you any rights to use it.


10. FUTURE REVISIONS OF THIS LICENSE

The Free Software Foundation may publish new, revised versions of the
GNU Free Documentation 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.  See
https://www.gnu.org/licenses/.

Each version of the License is given a distinguishing version number.
If the Document specifies that a particular numbered version of this
License "or any later version" applies to it, you have the option of
following the terms and conditions either of that specified version or
of any later version that has been published (not as a draft) by the
Free Software Foundation.  If the Document does not specify a version
number of this License, you may choose any version ever published (not
as a draft) by the Free Software Foundation.  If the Document
specifies that a proxy can decide which future versions of this
License can be used, that proxy's public statement of acceptance of a
version permanently authorizes you to choose that version for the
Document.

11. RELICENSING

"Massive Multiauthor Collaboration Site" (or "MMC Site") means any
World Wide Web server that publishes copyrightable works and also
provides prominent facilities for anybody to edit those works.  A
public wiki that anybody can edit is an example of such a server.  A
"Massive Multiauthor Collaboration" (or "MMC") contained in the site
means any set of copyrightable works thus published on the MMC site.

"CC-BY-SA" means the Creative Commons Attribution-Share Alike 3.0
license published by Creative Commons Corporation, a not-for-profit
corporation with a principal place of business in San Francisco,
California, as well as future copyleft versions of that license
published by that same organization.

"Incorporate" means to publish or republish a Document, in whole or in
part, as part of another Document.

An MMC is "eligible for relicensing" if it is licensed under this
License, and if all works that were first published under this License
somewhere other than this MMC, and subsequently incorporated in whole or
in part into the MMC, (1) had no cover texts or invariant sections, and
(2) were thus incorporated prior to November 1, 2008.

The operator of an MMC Site may republish an MMC contained in the site
under CC-BY-SA on the same site at any time before August 1, 2009,
provided the MMC is eligible for relicensing.


ADDENDUM: How to use this License for your documents

To use this License in a document you have written, include a copy of
the License in the document and put the following copyright and
license notices just after the title page:

    Copyright (c)  YEAR  YOUR NAME.
    Permission is granted to copy, distribute and/or modify this document
    under the terms of the GNU Free Documentation License, Version 1.3
    or any later version published by the Free Software Foundation;
    with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.
    A copy of the license is included in the section entitled "GNU
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If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts,
replace the "with...Texts." line with this:

    with the Invariant Sections being LIST THEIR TITLES, with the
    Front-Cover Texts being LIST, and with the Back-Cover Texts being LIST.

If you have Invariant Sections without Cover Texts, or some other
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</pre>
#+end_export

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** Variable index
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