Merge branch 'rust-lang:master' into draft-no-index

2022-04-04 18:59:39 -07:00 · 2022-04-04 18:59:39 -07:00 · 860a17d85a
parent 1cacef025d ba324cddb6
commit 860a17d85a
48 changed files with 1753 additions and 939 deletions
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@ -31,7 +31,8 @@ jobs:
            rust: stable
          - build: msrv
            os: ubuntu-latest
-            rust: 1.46.0
+            # sync MSRV with docs: guide/src/guide/installation.md
            rust: 1.54.0
    steps:
    - uses: actions/checkout@master
    - name: Install Rust
@ -48,4 +49,4 @@ jobs:
    - uses: actions/checkout@master
    - name: Install Rust
      run: rustup update stable && rustup default stable && rustup component add rustfmt
-    - run: cargo fmt -- --check
+    - run: cargo fmt --check
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@ -1,5 +1,50 @@
 # Changelog
 ## mdBook 0.4.17
 [a5fddfa...981b79b](https://github.com/rust-lang/mdBook/compare/a5fddfa...981b79b)
 ### Fixed
 - Fixed parsing of `output.html.print` configuration table.
  [#1775](https://github.com/rust-lang/mdBook/pull/1775)
 ## mdBook 0.4.16
 [68a5c09...a5fddfa](https://github.com/rust-lang/mdBook/compare/68a5c09...a5fddfa)
 ### Added
 - Added `output.html.print.page-break` config option to control whether or not
  there is a page break between chapters in the print output.
  [#1728](https://github.com/rust-lang/mdBook/pull/1728)
 - Added `output.html.playground.runnable` config option to globally disable
  the run button in code blocks.
  [#1546](https://github.com/rust-lang/mdBook/pull/1546)
 ### Changed
 - The `cargo serve` live reload websocket now uses the protocol, host, and
  port of the current page, allowing access through a proxy.
  [#1771](https://github.com/rust-lang/mdBook/pull/1771)
 - The 404 not-found page now includes the books title in the HTML title tag.
  [#1693](https://github.com/rust-lang/mdBook/pull/1693)
 - Migrated to clap 3.0 which which handles CLI option parsing.
  [#1731](https://github.com/rust-lang/mdBook/pull/1731)
 ### Fixed
 - Minor fixes to the markdown parser.
  [#1729](https://github.com/rust-lang/mdBook/pull/1729)
 - Fixed incorrect parsing in `SUMMARY.md` when it didn't start with a title.
  [#1744](https://github.com/rust-lang/mdBook/pull/1744)
 - Fixed duplicate anchor IDs for links in search results.
  [#1749](https://github.com/rust-lang/mdBook/pull/1749)
 ## mdBook 0.4.15
 [5eb7d46...68a5c09](https://github.com/rust-lang/mdBook/compare/5eb7d46...68a5c09)
 ### Changed
 - Major update to expand the documentation located at <https://rust-lang.github.io/mdBook/>.
  [#1709](https://github.com/rust-lang/mdBook/pull/1709)
  [#1710](https://github.com/rust-lang/mdBook/pull/1710)
 - Updated the markdown parser with various fixes for common-mark compliance.
  [#1712](https://github.com/rust-lang/mdBook/pull/1712)
 ## mdBook 0.4.14
 [ffa8284...c9b6be8](https://github.com/rust-lang/mdBook/compare/ffa8284...c9b6be8)
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@ -127,4 +127,4 @@ The following are instructions for updating [highlight.js](https://highlightjs.o
 1. Compare the language list that it spits out to the one in [`syntax-highlighting.md`](https://github.com/camelid/mdBook/blob/master/guide/src/format/theme/syntax-highlighting.md). If any are missing, add them to the list and rebuild (and update these docs). If any are added to the common set, add them to `syntax-highlighting.md`.
 1. Copy `build/highlight.min.js` to mdbook's directory [`highlight.js`](https://github.com/rust-lang/mdBook/blob/master/src/theme/highlight.js).
 1. Be sure to check the highlight.js [CHANGES](https://github.com/highlightjs/highlight.js/blob/main/CHANGES.md) for any breaking changes. Breaking changes that would affect users will need to wait until the next major release.
-1. Build mdbook with the new file and build some books with the new version and compare the output with a variety of languages to see if anything changes. (TODO: It would be nice to have a demo file in the repo to help with this.)
+1. Build mdbook with the new file and build some books with the new version and compare the output with a variety of languages to see if anything changes. The [test_book](https://github.com/rust-lang/mdBook/tree/master/test_book) contains a chapter with many languages to examine.
--- a/Cargo.lock
+++ b/Cargo.lock
@ -185,17 +185,27 @@ dependencies = [
 [[package]]
 name = "clap"
-version = "2.33.3"
+version = "3.0.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "37e58ac78573c40708d45522f0d80fa2f01cc4f9b4e2bf749807255454312002"
+checksum = "7a30c3bf9ff12dfe5dae53f0a96e0febcd18420d1c0e7fad77796d9d5c4b5375"
 dependencies = [
 "ansi_term",
 "atty",
 "bitflags",
 "indexmap",
 "lazy_static",
 "os_str_bytes",
 "strsim",
 "termcolor",
 "textwrap",
- "unicode-width",
+]
- "vec_map",
+
 [[package]]
 name = "clap_complete"
 version = "3.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d044e9db8cd0f68191becdeb5246b7462e4cf0c069b19ae00d1bf3fa9889498d"
 dependencies = [
 "clap",
 ]
 [[package]]
@ -473,15 +483,6 @@ dependencies = [
 "version_check",
 ]
 [[package]]
 name = "getopts"
 version = "0.2.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "14dbbfd5c71d70241ecf9e6f13737f7b5ce823821063188d7e46c41d371eebd5"
 dependencies = [
 "unicode-width",
 ]
 [[package]]
 name = "getrandom"
 version = "0.1.16"
@ -839,13 +840,14 @@ checksum = "a3e378b66a060d48947b590737b30a1be76706c8dd7b8ba0f2fe3989c68a853f"
 [[package]]
 name = "mdbook"
-version = "0.4.14"
+version = "0.4.17"
 dependencies = [
 "ammonia",
 "anyhow",
 "assert_cmd",
 "chrono",
 "clap",
 "clap_complete",
 "elasticlunr-rs",
 "env_logger",
 "futures-util",
@ -1062,6 +1064,15 @@ dependencies = [
 "winapi 0.3.9",
 ]
 [[package]]
 name = "os_str_bytes"
 version = "6.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8e22443d1643a904602595ba1cd8f7d896afe56d26712531c5ff73a15b2fbf64"
 dependencies = [
 "memchr",
 ]
 [[package]]
 name = "output_vt100"
 version = "0.1.2"
@ -1267,12 +1278,11 @@ dependencies = [
 [[package]]
 name = "pulldown-cmark"
-version = "0.8.0"
+version = "0.9.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ffade02495f22453cd593159ea2f59827aae7f53fa8323f756799b670881dcf8"
+checksum = "34f197a544b0c9ab3ae46c359a7ec9cbbb5c7bf97054266fecb7ead794a181d6"
 dependencies = [
 "bitflags",
 "getopts",
 "memchr",
 "unicase",
 ]
@ -1400,9 +1410,9 @@ dependencies = [
 [[package]]
 name = "regex"
-version = "1.5.4"
+version = "1.5.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d07a8629359eb56f1e2fb1652bb04212c072a87ba68546a04065d525673ac461"
+checksum = "1a11647b6b25ff05a515cb92c365cec08801e83423a235b51e231e1808747286"
 dependencies = [
 "aho-corasick",
 "memchr",
@ -1464,21 +1474,9 @@ dependencies = [
 [[package]]
 name = "semver"
-version = "0.11.0"
+version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f301af10236f6df4160f7c3f04eec6dbc70ace82d23326abad5edee88801c6b6"
+checksum = "568a8e6258aa33c13358f81fd834adb854c6f7c9468520910a9b1e8fac068012"
 dependencies = [
 "semver-parser",
 ]
 [[package]]
 name = "semver-parser"
 version = "0.10.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "00b0bef5b7f9e0df16536d3961cfb6e84331c065b4066afb39768d0e319411f7"
 dependencies = [
 "pest",
 ]
 [[package]]
 name = "serde"
@ -1600,9 +1598,9 @@ dependencies = [
 [[package]]
 name = "strsim"
-version = "0.8.0"
+version = "0.10.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8ea5119cdb4c55b55d432abb513a0429384878c15dde60cc77b1c99de1a95a6a"
+checksum = "73473c0e59e6d5812c5dfe2a064a6444949f089e20eec9a2e5506596494e4623"
 [[package]]
 name = "strum"
@ -1669,12 +1667,9 @@ dependencies = [
 [[package]]
 name = "textwrap"
-version = "0.11.0"
+version = "0.14.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d326610f408c7a4eb6f51c37c330e496b08506c9457c9d34287ecc38809fb060"
+checksum = "0066c8d12af8b5acd21e00547c3797fde4e8677254a7ee429176ccebbe93dd80"
 dependencies = [
 "unicode-width",
 ]
 [[package]]
 name = "time"
@ -1882,12 +1877,6 @@ version = "1.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8895849a949e7845e06bd6dc1aa51731a103c42707010a5b591c0038fb73385b"
 [[package]]
 name = "unicode-width"
 version = "0.1.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9337591893a19b88d8d87f2cec1e73fad5cdfd10e5a6f349f498ad6ea2ffb1e3"
 [[package]]
 name = "unicode-xid"
 version = "0.2.2"
@ -1912,12 +1901,6 @@ version = "0.7.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "09cc8ee72d2a9becf2f2febe0205bbed8fc6615b7cb429ad062dc7b7ddd036a9"
 [[package]]
 name = "vec_map"
 version = "0.8.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f1bddf1187be692e79c5ffeab891132dfb0f236ed36a43c7ed39f1165ee20191"
 [[package]]
 name = "version_check"
 version = "0.9.3"
--- a/Cargo.toml
+++ b/Cargo.toml
@ -1,6 +1,6 @@
 [package]
 name = "mdbook"
-version = "0.4.14"
+version = "0.4.17"
 authors = [
    "Mathieu David <mathieudavid@mathieudavid.org>",
    "Michael-F-Bryan <michaelfbryan@gmail.com>",
@ -18,15 +18,16 @@ description = "Creates a book from markdown files"
 [dependencies]
 anyhow = "1.0.28"
 chrono = "0.4"
-clap = "2.24"
+clap = { version = "3.0", features = ["cargo"] }
 clap_complete = "3.0"
 env_logger = "0.7.1"
 handlebars = "4.0"
 lazy_static = "1.0"
 log = "0.4"
 memchr = "2.0"
 opener = "0.5"
-pulldown-cmark = "0.8.0"
+pulldown-cmark = { version = "0.9.1", default-features = false }
-regex = "1.0.0"
+regex = "1.5.5"
 serde = "1.0"
 serde_derive = "1.0"
 serde_json = "1.0"
@ -52,7 +53,7 @@ ammonia = { version = "3", optional = true }
 assert_cmd = "1"
 predicates = "2"
 select = "0.5"
-semver = "0.11.0"
+semver = "1.0"
 pretty_assertions = "0.6"
 walkdir = "2.0"
--- a/README.md
+++ b/README.md
@ -6,233 +6,15 @@
 mdBook is a utility to create modern online books from Markdown files.
 Check out the **[User Guide]** for a list of features and installation and usage information.
 The User Guide also serves as a demonstration to showcase what a book looks like.
-## What does it look like?
+If you are interested in contributing to the development of mdBook, check out the [Contribution Guide].
 The [User Guide] for mdBook has been written in Markdown and is using mdBook to
 generate the online book-like website you can read. The documentation uses the
 latest version on GitHub and showcases the available features.
 ## Installation
 There are multiple ways to install mdBook.
 1. **Binaries**
   Binaries are available for download [here][releases]. Make sure to put the
   path to the binary into your `PATH`.
 2. **From Crates.io**
   This requires at least [Rust] 1.46 and Cargo to be installed. Once you have installed
   Rust, type the following in the terminal:
   ```
   cargo install mdbook
   ```
   This will download and compile mdBook for you, the only thing left to do is
   to add the Cargo bin directory to your `PATH`.
   **Note for automatic deployment**
   If you are using a script to do automatic deployments, we recommend that
   you specify a semver version range for mdBook when you install it through
   your script!
   This will constrain the server to install the latest **non-breaking**
   version of mdBook and will prevent your books from failing to build because
   we released a new version.
   You can also disable default features to speed up compile time.
   Example:
   ```
   cargo install mdbook --no-default-features --vers "^0.4.0"
   ```
 3. **From Git**
   The version published to crates.io will ever so slightly be behind the
   version hosted here on GitHub. If you need the latest version you can build
   the git version of mdBook yourself. Cargo makes this ***super easy***!
   ```
   cargo install --git https://github.com/rust-lang/mdBook.git mdbook
   ```
   Again, make sure to add the Cargo bin directory to your `PATH`.
 4. **For Contributions**
   If you want to contribute to mdBook you will have to clone the repository on
   your local machine:
   ```
   git clone https://github.com/rust-lang/mdBook.git
   ```
   `cd` into `mdBook/` and run
   ```
   cargo build
   ```
   The resulting binary can be found in `mdBook/target/debug/` under the name
   `mdBook` or `mdBook.exe`.
 ## Usage
 mdBook is primarily used as a command line tool, even though it exposes
 all its functionality as a Rust crate for integration in other projects.
 Here are the main commands you will want to run. For a more exhaustive
 explanation, check out the [User Guide].
 - `mdbook init <directory>`
    The init command will create a directory with the minimal boilerplate to
    start with. If the `<directory>` parameter is omitted, the current 
    directory will be used.
    ```
    book-test/
    ├── book
    └── src
        ├── chapter_1.md
        └── SUMMARY.md
    ```
    `book` and `src` are both directories. `src` contains the markdown files
    that will be used to render the output to the `book` directory.
    Please, take a look at the [CLI docs] for more information and some neat tricks.
 - `mdbook build`
    This is the command you will run to render your book, it reads the
    `SUMMARY.md` file to understand the structure of your book, takes the
    markdown files in the source directory as input and outputs static html
    pages that you can upload to a server.
 - `mdbook watch`
    When you run this command, mdbook will watch your markdown files to rebuild
    the book on every change. This avoids having to come back to the terminal
    to type `mdbook build` over and over again.
 - `mdbook serve`
    Does the same thing as `mdbook watch` but additionally serves the book at
    `http://localhost:3000` (port is changeable) and reloads the browser when a
    change occurs.
 - `mdbook clean`
    Delete directory in which generated book is located.
 ### 3rd Party Plugins
 The way a book is loaded and rendered can be configured by the user via third
 party plugins. These plugins are just programs which will be invoked during the
 build process and are split into roughly two categories, *preprocessors* and
 *renderers*.
 Preprocessors are used to transform a book before it is sent to a renderer.
 One example would be to replace all occurrences of
 `{{#include some_file.ext}}` with the contents of that file. Some existing
 preprocessors are:
 - `index` - a built-in preprocessor (enabled by default) which will transform
  all `README.md` chapters to `index.md` so `foo/README.md` can be accessed via
  the url `foo/` when published to a browser
 - `links` - a built-in preprocessor (enabled by default) for expanding the
  `{{# playground}}` and `{{# include}}` helpers in a chapter.
 - [`katex`](https://github.com/lzanini/mdbook-katex) - a preprocessor rendering LaTex equations to HTML.
 Renderers are given the final book so they can do something with it. This is
 typically used for, as the name suggests, rendering the document in a particular
 format, however there's nothing stopping a renderer from doing static analysis
 of a book in order to validate links or run tests. Some existing renderers are:
 - `html` - the built-in renderer which will generate a HTML version of the book
 - `markdown` - the built-in renderer (disabled by default) which will run
  preprocessors then output the resulting Markdown. Useful for debugging
  preprocessors.
 - [`linkcheck`] - a backend which will check that all links are valid
 - [`epub`] - an experimental EPUB generator
 - [`man`] - a backend that generates manual pages from the book
 > **Note for Developers:** Feel free to send us a PR if you've developed your
 > own plugin and want it mentioned here.
 A preprocessor or renderer is enabled by installing the appropriate program and
 then mentioning it in the book's `book.toml` file.
 ```console
 $ cargo install mdbook-linkcheck
 $ edit book.toml && cat book.toml
 [book]
 title = "My Awesome Book"
 authors = ["Michael-F-Bryan"]
 [output.html]
 [output.linkcheck]  # enable the "mdbook-linkcheck" renderer
 $ mdbook build
 2018-10-20 13:57:51 [INFO] (mdbook::book): Book building has started
 2018-10-20 13:57:51 [INFO] (mdbook::book): Running the html backend
 2018-10-20 13:57:53 [INFO] (mdbook::book): Running the linkcheck backend
 ```
 For more information on the plugin system, consult the [User Guide].
 ### As a library
 Aside from the command line interface, this crate can also be used as a
 library. This means that you could integrate it in an existing project, like a
 web-app for example. Since the command line interface is just a wrapper around
 the library functionality, when you use this crate as a library you have full
 access to all the functionality of the command line interface with an easy to
 use API and more!
 See the [User Guide] and the [API docs] for more information.
 ## Contributions
 Contributions are highly appreciated and encouraged! Don't hesitate to
 participate to discussions in the issues, propose new features and ask for
 help.
 If you are just starting out with Rust, there are a series of issues that are
 tagged [E-Easy] and **we will gladly mentor you** so that you can successfully
 go through the process of fixing a bug or adding a new feature! Let us know if
 you need any help.
 For more info about contributing, check out our [contribution guide] which helps
 you go through the build and contribution process!
 There is also a [rendered version][master-docs] of the latest API docs
 available, for those hacking on `master`.
 ## License
 All the code in this repository is released under the ***Mozilla Public License v2.0***, for more information take a look at the [LICENSE] file.
 [User Guide]: https://rust-lang.github.io/mdBook/
 [API docs]: https://docs.rs/mdbook/*/mdbook/
 [E-Easy]: https://github.com/rust-lang/mdBook/issues?q=is%3Aopen+is%3Aissue+label%3AE-Easy
 [contribution guide]: https://github.com/rust-lang/mdBook/blob/master/CONTRIBUTING.md
 [LICENSE]: https://github.com/rust-lang/mdBook/blob/master/LICENSE
 [releases]: https://github.com/rust-lang/mdBook/releases
 [Rust]: https://www.rust-lang.org/
 [CLI docs]: http://rust-lang.github.io/mdBook/cli/init.html
 [master-docs]: http://rust-lang.github.io/mdBook/
 [`linkcheck`]: https://crates.io/crates/mdbook-linkcheck
 [`epub`]: https://crates.io/crates/mdbook-epub
 [`man`]: https://crates.io/crates/mdbook-man
--- a/examples/nop-preprocessor.rs
+++ b/examples/nop-preprocessor.rs
@ -1,5 +1,5 @@
 use crate::nop_lib::Nop;
-use clap::{App, Arg, ArgMatches, SubCommand};
+use clap::{App, Arg, ArgMatches};
 use mdbook::book::Book;
 use mdbook::errors::Error;
 use mdbook::preprocess::{CmdPreprocessor, Preprocessor, PreprocessorContext};
@ -7,12 +7,12 @@ use semver::{Version, VersionReq};
 use std::io;
 use std::process;
-pub fn make_app() -> App<'static, 'static> {
+pub fn make_app() -> App<'static> {
    App::new("nop-preprocessor")
        .about("A mdbook preprocessor which does precisely nothing")
        .subcommand(
-            SubCommand::with_name("supports")
+            App::new("supports")
-                .arg(Arg::with_name("renderer").required(true))
+                .arg(Arg::new("renderer").required(true))
                .about("Check whether a renderer is supported by this preprocessor"),
        )
 }
--- a/guide/src/README.md
+++ b/guide/src/README.md
@ -1,22 +1,30 @@
 # Introduction
-**mdBook** is a command line tool and Rust crate to create books with Markdown. The output resembles tools like Gitbook,
+**mdBook** is a command line tool to create books with Markdown.
-and is ideal for creating product or API documentation, tutorials, course materials or anything that requires a clean,
+It is ideal for creating product or API documentation, tutorials, course materials or anything that requires a clean,
-easily navigable and customizable presentation. mdBook is written in [Rust](https://www.rust-lang.org); its performance
+easily navigable and customizable presentation.
 and simplicity made it ideal for use as a tool to publish directly to hosted websites such
 as [GitHub Pages](https://pages.github.com) via automation. This guide, in fact, serves as both the mdBook documentation
 and a fine example of what mdBook produces.
-mdBook includes built in support for both preprocessing your Markdown and alternative renderers for producing formats
+* Lightweight [Markdown] syntax helps you focus more on your content
-other than HTML. These facilities also enable other functionality such as
+* Integrated [search] support
-validation. [Searching](https://crates.io/search?q=mdbook&sort=relevance) Rust's [crates.io](https://crates.io) is a
+* Color [syntax highlighting] for code blocks for many different languages
-great way to discover more extensions.
+* [Theme] files allow customizing the formatting of the output
 * [Preprocessors] can provide extensions for custom syntax and modifying content
 * [Backends] can render the output to multiple formats
 * Written in [Rust] for speed, safety, and simplicity
 * Automated testing of [Rust code samples]
-## API Documentation
+This guide is an example of what mdBook produces.
 mdBook is used by the Rust programming language project, and [The Rust Programming Language][trpl] book is another fine example of mdBook in action.
-In addition to the above features, mdBook also has a Rust [API](https://docs.rs/mdbook/*/mdbook/). This allows you to
+[Markdown]: format/markdown.md
-write your own preprocessor or renderer, as well as incorporate mdBook features into other applications.
+[search]: guide/reading.md#search
-The [For Developers](for_developers) section of this guide contains more information and some examples.
+[syntax highlighting]: format/theme/syntax-highlighting.md
 [theme]: format/theme/index.html
 [preprocessors]: format/configuration/preprocessors.md
 [backends]: format/configuration/renderers.md
 [Rust]: https://www.rust-lang.org/
 [trpl]: https://doc.rust-lang.org/book/
 [Rust code samples]: cli/test.md
 ## Contributing
--- a/guide/src/SUMMARY.md
+++ b/guide/src/SUMMARY.md
@ -1,6 +1,15 @@
 # Summary
- [Introduction](README.md)
+[Introduction](README.md)
 # User Guide
 - [Installation](guide/installation.md)
 - [Reading Books](guide/reading.md)
 - [Creating a Book](guide/creating.md)
 # Reference Guide
 - [Command Line Tool](cli/README.md)
    - [init](cli/init.md)
    - [build](cli/build.md)
@ -8,6 +17,7 @@
    - [serve](cli/serve.md)
    - [test](cli/test.md)
    - [clean](cli/clean.md)
    - [completions](cli/completions.md)
 - [Format](format/README.md)
    - [SUMMARY.md](format/summary.md)
        - [Draft chapter]()
--- a/guide/src/cli/README.md
+++ b/guide/src/cli/README.md
@ -1,55 +1,14 @@
 # Command Line Tool
-mdBook can be used either as a command line tool or a [Rust
+The `mdbook` command-line tool is used to create and build books.
-crate](https://crates.io/crates/mdbook). Let's focus on the command line tool
+After you have [installed](../guide/installation.md) `mdbook`, you can run the `mdbook help` command in your terminal to view the available commands.
 capabilities first.
-## Install From Binaries
+This following sections provide in-depth information on the different commands available.
-Precompiled binaries are provided for major platforms on a best-effort basis.
+* [`mdbook init <directory>`](init.md) — Creates a new book with minimal boilerplate to start with.
-Visit [the releases page](https://github.com/rust-lang/mdBook/releases)
+* [`mdbook build`](build.md) — Renders the book.
-to download the appropriate version for your platform.
+* [`mdbook watch`](watch.md) — Rebuilds the book any time a source file changes.
-
+* [`mdbook serve`](serve.md) — Runs a web server to view the book, and rebuilds on changes.
-## Install From Source
+* [`mdbook test`](test.md) — Tests Rust code samples.
-
+* [`mdbook clean`](clean.md) — Deletes the rendered output.
-mdBook can also be installed by compiling the source code on your local machine.
+* [`mdbook completions`](completions.md) — Support for shell auto-completion.
 ### Pre-requisite
 mdBook is written in **[Rust](https://www.rust-lang.org/)** and therefore needs
 to be compiled with **Cargo**. If you haven't already installed Rust, please go
 ahead and [install it](https://www.rust-lang.org/tools/install) now.
 ### Install Crates.io version
 Installing mdBook is relatively easy if you already have Rust and Cargo
 installed. You just have to type this snippet in your terminal:
 ```bash
 cargo install mdbook
 ```
 This will fetch the source code for the latest release from
 [Crates.io](https://crates.io/) and compile it. You will have to add Cargo's
 `bin` directory to your `PATH`.
 Run `mdbook help` in your terminal to verify if it works. Congratulations, you
 have installed mdBook!
 ### Install Git version
 The **[git version](https://github.com/rust-lang/mdBook)** contains all
 the latest bug-fixes and features, that will be released in the next version on
 **Crates.io**, if you can't wait until the next release. You can build the git
 version yourself. Open your terminal and navigate to the directory of you
 choice. We need to clone the git repository and then build it with Cargo.
 ```bash
 git clone --depth=1 https://github.com/rust-lang/mdBook.git
 cd mdBook
 cargo build --release
 ```
 The executable `mdbook` will be in the `./target/release` folder, this should be
 added to the path.
--- a/guide/src/cli/completions.md
+++ b/guide/src/cli/completions.md
@ -0,0 +1,16 @@
 # The completions command
 The completions command is used to generate auto-completions for some common shells.
 This means when you type `mdbook` in your shell, you can then press your shell's auto-complete key (usually the Tab key) and it may display what the valid options are, or finish partial input.
 The completions first need to be installed for your shell:
 ```bash
 mdbook completions bash > ~/.local/share/bash-completion/completions/mdbook
 ```
 The command prints a completion script for the given shell.
 Run `mdbook completions --help` for a list of supported shells.
 Where to place the completions depend on which shell you are using and your operating system.
 Consult your shell's documentation for more information one where to place the script.
--- a/guide/src/continuous-integration.md
+++ b/guide/src/continuous-integration.md
@ -1,154 +1,121 @@
 # Running `mdbook` in Continuous Integration
-While the following examples use Travis CI, their principles should
+There are a variety of services such as [GitHub Actions] or [GitLab CI/CD] which can be used to test and deploy your book automatically.
 straightforwardly transfer to other continuous integration providers as well.
-## Ensuring Your Book Builds and Tests Pass
+The following provides some general guidelines on how to configure your service to run mdBook.
 Specific recipes can be found at the [Automated Deployment] wiki page.
-Here is a sample Travis CI `.travis.yml` configuration that ensures `mdbook
+[GitHub Actions]: https://docs.github.com/en/actions
-build` and `mdbook test` run successfully. The key to fast CI turnaround times
+[GitLab CI/CD]: https://docs.gitlab.com/ee/ci/
-is caching `mdbook` installs, so that you aren't compiling `mdbook` on every CI
+[Automated Deployment]: https://github.com/rust-lang/mdBook/wiki/Automated-Deployment
 run.
-```yaml
+## Installing mdBook
 language: rust
 sudo: false
-cache:
+There are several different strategies for installing mdBook.
-  - cargo
+The particular method depends on your needs and preferences.
-rust:
+### Pre-compiled binaries
  - stable
-before_script:
+Perhaps the easiest method is to use the pre-compiled binaries found on the [GitHub Releases page][releases].
-  - (test -x $HOME/.cargo/bin/cargo-install-update || cargo install cargo-update)
+A simple approach would be to use the popular `curl` CLI tool to download the executable:
  - (test -x $HOME/.cargo/bin/mdbook || cargo install --vers "^0.3" mdbook)
  - cargo install-update -a
-script:
+```sh
-  - mdbook build && mdbook test # In case of custom book path: mdbook build path/to/mybook && mdbook test path/to/mybook
+mkdir bin
 curl -sSL https://github.com/rust-lang/mdBook/releases/download/v0.4.17/mdbook-v0.4.17-x86_64-unknown-linux-gnu.tar.gz | tar -xz --directory=bin
 bin/mdbook build
 ```
-## Deploying Your Book to GitHub Pages
+Some considerations for this approach:
-Following these instructions will result in your book being published to GitHub
+* This is relatively fast, and does not necessarily require dealing with caching.
-pages after a successful CI run on your repository's `master` branch.
+* This does not require installing Rust.
 * Specifying a specific URL means you have to manually update your script to get a new version.
  This may be a benefit if you want to lock to a specific version.
  However, some users prefer to automatically get a newer version when they are published.
 * You are reliant on the GitHub CDN being available.
-First, create a new GitHub "Personal Access Token" with the "public_repo"
+[releases]: https://github.com/rust-lang/mdBook/releases
 permissions (or "repo" for private repositories). Go to your repository's Travis
 CI settings page and add an environment variable named `GITHUB_TOKEN` that is
 marked secure and *not* shown in the logs.
-Whilst still in your repository's settings page, navigate to Options and change the 
+### Building from source
 Source on GitHub pages to `gh-pages`.
-Then, append this snippet to your `.travis.yml` and update the path to the
+Building from source will require having Rust installed.
-`book` directory:
+Some services have Rust pre-installed, but if your service does not, you will need to add a step to install it.
-```yaml
+After Rust is installed, `cargo install` can be used to build and install mdBook.
-deploy:
+We recommend using a SemVer version specifier so that you get the latest **non-breaking** version of mdBook.
-  provider: pages
+For example:
-  skip-cleanup: true
+
-  github-token: $GITHUB_TOKEN
+```sh
-  local-dir: book # In case of custom book path: path/to/mybook/book
+cargo install mdbook --no-default-features --features search --vers "^0.4" --locked
  keep-history: false
  on:
    branch: main
 ```
-That's it!
+This includes several recommended options:
-Note: Travis has a new [dplv2](https://blog.travis-ci.com/2019-08-27-deployment-tooling-dpl-v2-preview-release) configuration that is currently in beta. To use this new format, update your `.travis.yml` file to:
+* `--no-default-features` — Disables features like the HTTP server used by `mdbook serve` that is likely not needed on CI.
  This will speed up the build time significantly.
 * `--features search` — Disabling default features means you should then manually enable features that you want, such as the built-in [search] capability.
 * `--vers "^0.4"` — This will install the most recent version of the `0.4` series.
  However, versions after like `0.5.0` won't be installed, as they may break your build.
  Cargo will automatically upgrade mdBook if you have an older version already installed.
 * `--locked` — This will use the dependencies that were used when mdBook was released.
  Without `--locked`, it will use the latest version of all dependencies, which may include some fixes since the last release, but may also (rarely) cause build problems.
-```yaml
+You will likely want to investigate caching options, as building mdBook can be somewhat slow.
 language: rust
 os: linux
 dist: xenial
-cache:
+[search]: guide/reading.md#search
  - cargo
-rust:
+## Running tests
  - stable
-before_script:
+You may want to run tests using [`mdbook test`] every time you push a change or create a pull request.
-  - (test -x $HOME/.cargo/bin/cargo-install-update || cargo install cargo-update)
+This can be used to validate Rust code examples in the book.
  - (test -x $HOME/.cargo/bin/mdbook || cargo install --vers "^0.3" mdbook)
  - cargo install-update -a
-script:
+This will require having Rust installed.
-  - mdbook build && mdbook test # In case of custom book path: mdbook build path/to/mybook && mdbook test path/to/mybook
+Some services have Rust pre-installed, but if your service does not, you will need to add a step to install it.
-  
+
-deploy:
+Other than making sure the appropriate version of Rust is installed, there's not much more than just running `mdbook test` from the book directory.
-  provider: pages
+
-  strategy: git
+You may also want to consider running other kinds of tests, like [mdbook-linkcheck] which will check for broken links.
-  edge: true
+Or if you have your own style checks, spell checker, or any other tests it might be good to run them in CI.
-  cleanup: false
+
-  github-token: $GITHUB_TOKEN
+[`mdbook test`]: cli/test.md
-  local-dir: book # In case of custom book path: path/to/mybook/book
+[mdbook-linkcheck]: https://github.com/Michael-F-Bryan/mdbook-linkcheck#continuous-integration
-  keep-history: false
+
-  on:
+## Deploying
-    branch: main
+
-  target_branch: gh-pages
+You may want to automatically deploy your book.
 Some may want to do this with every time a change is pushed, and others may want to only deploy when a specific release is tagged.
 You'll also need to understand the specifics on how to push a change to your web service.
 For example, [GitHub Pages] just requires committing the output onto a specific git branch.
 Other services may require using something like SSH to connect to a remote server.
 The basic outline is that you need to run `mdbook build` to generate the output, and then transfer the files (which are in the `book` directory) to the correct location.
 You may then want to consider if you need to invalidate any caches on your web service.
 See the [Automated Deployment] wiki page for examples of various different services.
 [GitHub Pages]: https://docs.github.com/en/pages
 ### 404 handling
 mdBook automatically generates a 404 page to be used for broken links.
 The default output is a file named `404.html` at the root of the book.
 Some services like [GitHub Pages] will automatically use this page for broken links.
 For other services, you may want to consider configuring the web server to use this page as it will provide the reader navigation to get back to the book.
 If your book is not deployed at the root of the domain, then you should set the [`output.html.site-url`] setting so that the 404 page works correctly.
 It needs to know where the book is deployed in order to load the static files (like CSS) correctly.
 For example, this guide is deployed at <https://rust-lang.github.io/mdBook/>, and the `site-url` setting is configured like this:
 ```toml
 # book.toml
 [output.html]
 site-url = "/mdBook/"
 ```
-### Deploying to GitHub Pages manually
+You can customize the look of the 404 page by creating a file named `src/404.md` in your book.
 If you want to use a different filename, you can set [`output.html.input-404`] to a different filename.
-If your CI doesn't support GitHub pages, or you're deploying somewhere else
+[`output.html.site-url`]: format/configuration/renderers.md#html-renderer-options
-with integrations such as Github Pages:
+[`output.html.input-404`]: format/configuration/renderers.md#html-renderer-options
 *note: you may want to use different tmp dirs*:
 ```console
 $> git worktree add /tmp/book gh-pages
 $> mdbook build
 $> rm -rf /tmp/book/* # this won't delete the .git directory
 $> cp -rp book/* /tmp/book/
 $> cd /tmp/book
 $> git add -A
 $> git commit 'new book message'
 $> git push origin gh-pages
 $> cd -
 ```
 Or put this into a Makefile rule:
 ```makefile
 .PHONY: deploy
 deploy: book
 	@echo "====> deploying to github"
 	git worktree add /tmp/book gh-pages
 	rm -rf /tmp/book/*
 	cp -rp book/* /tmp/book/
 	cd /tmp/book && \
 		git add -A && \
 		git commit -m "deployed on $(shell date) by ${USER}" && \
 		git push origin gh-pages
 ```
 ## Deploying Your Book to GitLab Pages
 Inside your repository's project root, create a file named `.gitlab-ci.yml` with the following contents:
 ```yml
 stages:
    - deploy
 pages:
  stage: deploy
  image: rust
  variables:
    CARGO_HOME: $CI_PROJECT_DIR/cargo
  before_script:
    - export PATH="$PATH:$CARGO_HOME/bin"
    - mdbook --version || cargo install mdbook
  script:
    - mdbook build -d public
  rules:
    - if: '$CI_COMMIT_REF_NAME == "master"'
  artifacts:
    paths:
      - public
  cache:
    paths:
      - $CARGO_HOME/bin
 ```
 After you commit and push this new file, GitLab CI will run and your book will be available!
--- a/guide/src/for_developers/README.md
+++ b/guide/src/for_developers/README.md
@ -24,8 +24,9 @@ The process of rendering a book project goes through several steps.
       exist
    - Load the book chapters into memory
    - Discover which preprocessors/backends should be used
-2. Run the preprocessors
+2. For each backend:
-3. Call each backend in turn
+   1. Run all the preprocessors.
   2. Call the backend to render the processed result.
 ## Using `mdbook` as a Library
--- a/guide/src/for_developers/backends.md
+++ b/guide/src/for_developers/backends.md
@ -5,23 +5,17 @@ rendering process. This program is passed a JSON representation of the book and
 configuration information via `stdin`. Once the backend receives this
 information it is free to do whatever it wants.
-There are already several alternative backends on GitHub which can be used as a
+See [Configuring Renderers](../format/configuration/renderers.md) for more information about using backends.
 rough example of how this is accomplished in practice.
- [mdbook-linkcheck] - a simple program for verifying the book doesn't contain
+The community has developed several backends.
-  any broken links
+See the [Third Party Plugins] wiki page for a list of available backends.
- [mdbook-epub] - an EPUB renderer
+
- [mdbook-test] - a program to run the book's contents through [rust-skeptic] to
+## Setting Up
  verify everything compiles and runs correctly (similar to `rustdoc --test`)
 - [mdbook-man] - generate manual pages from the book
 This page will step you through creating your own alternative backend in the form
 of a simple word counting program. Although it will be written in Rust, there's
 no reason why it couldn't be accomplished using something like Python or Ruby.
 ## Setting Up
 First you'll want to create a new binary program and add `mdbook` as a
 dependency.
@ -330,39 +324,6 @@ generation or a warning).
 All environment variables are passed through to the backend, allowing you to use
 the usual `RUST_LOG` to control logging verbosity.
 ## Handling missing backends
 If you enable a backend that isn't installed, the default behavior is to throw an error:
 ```text
 The command `mdbook-wordcount` wasn't found, is the "wordcount" backend installed?
 If you want to ignore this error when the "wordcount" backend is not installed,
 set `optional = true` in the `[output.wordcount]` section of the book.toml configuration file.
 ```
 This behavior can be changed by marking the backend as optional.
 ```diff
  [book]
  title = "mdBook Documentation"
  description = "Create book from markdown files. Like Gitbook but implemented in Rust"
  authors = ["Mathieu David", "Michael-F-Bryan"]
  [output.html]
  [output.wordcount]
  command = "python /path/to/wordcount.py"
 + optional = true
 ```
 This demotes the error to a warning, and it will instead look like this:
 ```text
 The command was not found, but was marked as optional.
    Command: wordcount
 ```
 ## Wrapping Up
 Although contrived, hopefully this example was enough to show how you'd create
@ -375,11 +336,7 @@ as a good example of how it's done in real life, so feel free to skim through
 the source code or ask questions.
-[mdbook-linkcheck]: https://github.com/Michael-F-Bryan/mdbook-linkcheck
+[Third Party Plugins]: https://github.com/rust-lang/mdBook/wiki/Third-party-plugins
 [mdbook-epub]: https://github.com/Michael-F-Bryan/mdbook-epub
 [mdbook-test]: https://github.com/Michael-F-Bryan/mdbook-test
 [mdbook-man]: https://github.com/vv9k/mdbook-man
 [rust-skeptic]: https://github.com/budziq/rust-skeptic
 [`RenderContext`]: https://docs.rs/mdbook/*/mdbook/renderer/struct.RenderContext.html
 [`RenderContext::from_json()`]: https://docs.rs/mdbook/*/mdbook/renderer/struct.RenderContext.html#method.from_json
 [`semver`]: https://crates.io/crates/semver
--- a/guide/src/for_developers/preprocessors.md
+++ b/guide/src/for_developers/preprocessors.md
@ -5,35 +5,18 @@ book is loaded and before it gets rendered, allowing you to update and mutate
 the book. Possible use cases are:
 - Creating custom helpers like `\{{#include /path/to/file.md}}`
 - Updating links so `[some chapter](some_chapter.md)` is automatically changed
  to `[some chapter](some_chapter.html)` for the HTML renderer
 - Substituting in latex-style expressions (`$$ \frac{1}{3} $$`) with their
  mathjax equivalents
 See [Configuring Preprocessors](../format/configuration/preprocessors.md) for more information about using preprocessors.
 ## Hooking Into MDBook
 MDBook uses a fairly simple mechanism for discovering third party plugins.
-A new table is added to `book.toml` (e.g. `preprocessor.foo` for the `foo`
+A new table is added to `book.toml` (e.g. `[preprocessor.foo]` for the `foo`
 preprocessor) and then `mdbook` will try to invoke the `mdbook-foo` program as
 part of the build process.
 A preprocessor can be hard-coded to specify which backend(s) it should be run
 for with the `preprocessor.foo.renderer` key. For example, it doesn't make sense for 
 [MathJax](../format/mathjax.md) to be used for non-HTML renderers.
 ```toml
 [book]
 title = "My Book"
 authors = ["Michael-F-Bryan"]
 [preprocessor.foo]
 # The command can also be specified manually
 command = "python3 /path/to/foo.py"
 # Only run the `foo` preprocessor for the HTML and EPUB renderer
 renderer = ["html", "epub"]
 ```
 Once the preprocessor has been defined and the build process starts, mdBook executes the command defined in the `preprocessor.foo.command` key twice.
 The first time it runs the preprocessor to determine if it supports the given renderer.
 mdBook passes two arguments to the process: the first argument is the string `supports` and the second argument is the renderer name.
@ -78,7 +61,7 @@ The `chapter.content` is just a string which happens to be markdown. While it's
 entirely possible to use regular expressions or do a manual find & replace,
 you'll probably want to process the input into something more computer-friendly.
 The [`pulldown-cmark`][pc] crate implements a production-quality event-based
-Markdown parser, with the [`pulldown-cmark-to-cmark`][pctc] allowing you to
+Markdown parser, with the [`pulldown-cmark-to-cmark`][pctc] crate allowing you to
 translate events back into markdown text.
 The following code block shows how to remove all emphasis from markdown,
--- a/guide/src/format/configuration/general.md
+++ b/guide/src/format/configuration/general.md
@ -62,6 +62,11 @@ language = "en"
 Options for the Rust language, relevant to running tests and playground
 integration.
 ```toml
 [rust]
 edition = "2015"   # the default edition for code blocks
 ```
 - **edition**: Rust edition to use by default for the code snippets. Default
  is "2015". Individual code blocks can be controlled with the `edition2015`, 
  `edition2018` or `edition2021` annotations, such as:
@ -77,8 +82,16 @@ integration.
 This controls the build process of your book.
 ```toml
 [build]
 build-dir = "book"                # the directory where the output is placed
 create-missing = true             # whether or not to create missing pages
 use-default-preprocessors = true  # use the default preprocessors
 ```
 - **build-dir:** The directory to put the rendered book in. By default this is
  `book/` in the book's root directory.
  This can overridden with the `--dest-dir` CLI option.
 - **create-missing:** By default, any missing files specified in `SUMMARY.md`
  will be created when the book is built (i.e. `create-missing = true`). If this
  is `false` then the build process will instead exit with an error if any files
--- a/guide/src/format/configuration/preprocessors.md
+++ b/guide/src/format/configuration/preprocessors.md
@ -1,51 +1,58 @@
 # Configuring Preprocessors
-The following preprocessors are available and included by default:
+Preprocessors are extensions that can modify the raw Markdown source before it gets sent to the renderer.
- `links`: Expand the `{{ #playground }}`, `{{ #include }}`, and `{{ #rustdoc_include }}` handlebars
+The following preprocessors are built-in and included by default:
 - `links`: Expands the `{{ #playground }}`, `{{ #include }}`, and `{{ #rustdoc_include }}` handlebars
  helpers in a chapter to include the contents of a file.
  See [Including files] for more.
 - `index`: Convert all chapter files named `README.md` into `index.md`. That is
  to say, all `README.md` would be rendered to an index file `index.html` in the
  rendered book.
 The built-in preprocessors can be disabled with the [`build.use-default-preprocessors`] config option.
-**book.toml**
+The community has developed several preprocessors.
-```toml
+See the [Third Party Plugins] wiki page for a list of available preprocessors.
 [build]
 build-dir = "build"
 create-missing = false
-[preprocessor.links]
+For information on how to create a new preprocessor, see the [Preprocessors for Developers] chapter.
-[preprocessor.index]
+[Including files]: ../mdbook.md#including-files
-```
+[`build.use-default-preprocessors`]: general.md#build-options
 [Third Party Plugins]: https://github.com/rust-lang/mdBook/wiki/Third-party-plugins
 [Preprocessors for Developers]: ../../for_developers/preprocessors.md
-### Custom Preprocessor Configuration
+## Custom Preprocessor Configuration
-Like renderers, preprocessor will need to be given its own table (e.g.
+Preprocessors can be added by including a `preprocessor` table in `book.toml` with the name of the preprocessor.
-`[preprocessor.mathjax]`). In the section, you may then pass extra
+For example, if you have a preprocessor called `mdbook-example`, then you can include it with:
 configuration to the preprocessor by adding key-value pairs to the table.
 For example
 ```toml
-[preprocessor.links]
+[preprocessor.example]
 # set the renderers this preprocessor will run for
 renderers = ["html"]
 some_extra_feature = true
 ```
-#### Locking a Preprocessor dependency to a renderer
+With this table, mdBook will execute the `mdbook-example` preprocessor.
 This table can include additional key-value pairs that are specific to the preprocessor.
 For example, if our example prepocessor needed some extra configuration options:
 ```toml
 [preprocessor.example]
 some-extra-feature = true
 ```
 ## Locking a Preprocessor dependency to a renderer
 You can explicitly specify that a preprocessor should run for a renderer by
 binding the two together.
 ```toml
-[preprocessor.mathjax]
+[preprocessor.example]
-renderers = ["html"]  # mathjax only makes sense with the HTML renderer
+renderers = ["html"]  # example preprocessor only runs with the HTML renderer
 ```
-### Provide Your Own Command
+## Provide Your Own Command
 By default when you add a `[preprocessor.foo]` table to your `book.toml` file,
 `mdbook` will try to invoke the `mdbook-foo` executable. If you want to use a
@ -57,7 +64,7 @@ be overridden by adding a `command` field.
 command = "python random.py"
 ```
-### Require A Certain Order
+## Require A Certain Order
 The order in which preprocessors are run can be controlled with the `before` and `after` fields.
 For example, suppose you want your `linenos` preprocessor to process lines that may have been `{{#include}}`d; then you want it to run after the built-in `links` preprocessor, which you can require using either the `before` or `after` field:
--- a/guide/src/format/configuration/renderers.md
+++ b/guide/src/format/configuration/renderers.md
@ -1,9 +1,115 @@
 # Configuring Renderers
-### HTML renderer options
+Renderers (also called "backends") are responsible for creating the output of the book.
-The HTML renderer has a couple of options as well. All the options for the
+The following backends are built-in:
-renderer need to be specified under the TOML table `[output.html]`.
+
 * [`html`](#html-renderer-options) — This renders the book to HTML.
  This is enabled by default if no other `[output]` tables are defined in `book.toml`.
 * [`markdown`](#markdown-renderer) — This outputs the book as markdown after running the preprocessors.
  This is useful for debugging preprocessors.
 The community has developed several backends.
 See the [Third Party Plugins] wiki page for a list of available backends.
 For information on how to create a new backend, see the [Backends for Developers] chapter.
 [Third Party Plugins]: https://github.com/rust-lang/mdBook/wiki/Third-party-plugins
 [Backends for Developers]: ../../for_developers/backends.md
 ## Output tables
 Backends can be added by including a `output` table in `book.toml` with the name of the backend.
 For example, if you have a backend called `mdbook-wordcount`, then you can include it with:
 ```toml
 [output.wordcount]
 ```
 With this table, mdBook will execute the `mdbook-wordcount` backend.
 This table can include additional key-value pairs that are specific to the backend.
 For example, if our example backend needed some extra configuration options:
 ```toml
 [output.wordcount]
 ignores = ["Example Chapter"]
 ```
 If you define any `[output]` tables, then the `html` backend is not enabled by default.
 If you want to keep the `html` backend running, then just include it in the `book.toml` file.
 For example:
 ```toml
 [book]
 title = "My Awesome Book"
 [output.wordcount]
 [output.html]
 ```
 If more than one `output` table is included, this changes the behavior for the layout of the output directory.
 If there is only one backend, then it places its output directly in the `book` directory (see [`build.build-dir`] to override this location).
 If there is more than one backend, then each backend is placed in a separate directory underneath `book`.
 For example, the above would have directories `book/html` and `book/wordcount`.
 [`build.build-dir`]: general.md#build-options
 ### Custom backend commands
 By default when you add an `[output.foo]` table to your `book.toml` file,
 `mdbook` will try to invoke the `mdbook-foo` executable.
 If you want to use a different program name or pass in command-line arguments,
 this behaviour can be overridden by adding a `command` field.
 ```toml
 [output.random]
 command = "python random.py"
 ```
 ### Optional backends
 If you enable a backend that isn't installed, the default behavior is to throw an error.
 This behavior can be changed by marking the backend as optional:
 ```toml
 [output.wordcount]
 optional = true
 ```
 This demotes the error to a warning.
 ## HTML renderer options
 The HTML renderer has a variety of options detailed below.
 They should be specified in the `[output.html]` table of the `book.toml` file.
 ```toml
 # Example book.toml file with all output options.
 [book]
 title = "Example book"
 authors = ["John Doe", "Jane Doe"]
 description = "The example book covers examples."
 [output.html]
 theme = "my-theme"
 default-theme = "light"
 preferred-dark-theme = "navy"
 curly-quotes = true
 mathjax-support = false
 copy-fonts = true
 additional-css = ["custom.css", "custom2.css"]
 additional-js = ["custom.js"]
 no-section-label = false
 git-repository-url = "https://github.com/rust-lang/mdBook"
 git-repository-icon = "fa-github"
 edit-url-template = "https://github.com/rust-lang/mdBook/edit/master/guide/{path}"
 site-url = "/example-book/"
 cname = "myproject.rs"
 input-404 = "not-found.md"
 ```
 The following configuration options are available:
@ -30,34 +136,22 @@ The following configuration options are available:
 - **additional-js:** If you need to add some behaviour to your book without
  removing the current behaviour, you can specify a set of JavaScript files that
  will be loaded alongside the default one.
- **print:** A subtable for configuration print settings. mdBook by default adds
+- **no-section-label:** mdBook by defaults adds numeric section labels in the table of
  support for printing out the book as a single page. This is accessed using the
  print icon on the top right of the book.
 - **no-section-label:** mdBook by defaults adds section label in table of
  contents column. For example, "1.", "2.1". Set this option to true to disable
  those labels. Defaults to `false`.
 - **fold:** A subtable for configuring sidebar section-folding behavior.
 - **playground:** A subtable for configuring various playground settings.
 - **search:** A subtable for configuring the in-browser search functionality.
  mdBook must be compiled with the `search` feature enabled (on by default).
 - **git-repository-url:**  A url to the git repository for the book. If provided
  an icon link will be output in the menu bar of the book.
 - **git-repository-icon:** The FontAwesome icon class to use for the git
-  repository link. Defaults to `fa-github`.
+  repository link. Defaults to `fa-github` which looks like <i class="fa fa-github"></i>.
  If you are not using GitHub, another option to consider is `fa-code-fork` which looks like <i class="fa fa-code-fork"></i>.
 - **edit-url-template:** Edit url template, when provided shows a
-  "Suggest an edit" button for directly jumping to editing the currently
+  "Suggest an edit" button (which looks like <i class="fa fa-edit"></i>) for directly jumping to editing the currently
  viewed page. For e.g. GitHub projects set this to
  `https://github.com/<owner>/<repo>/edit/master/{path}` or for
  Bitbucket projects set it to
  `https://bitbucket.org/<owner>/<repo>/src/master/{path}?mode=edit`
  where {path} will be replaced with the full path of the file in the
  repository.
 - **redirect:** A subtable used for generating redirects when a page is moved.
  The table contains key-value pairs where the key is where the redirect file
  needs to be created, as an absolute path from the build directory, (e.g.
  `/appendices/bibliography.html`). The value can be any valid URI the
  browser should navigate to (e.g. `https://rust-lang.org/`,
  `/overview.html`, or `../bibliography.html`).
 - **input-404:** The name of the markdown file used for missing files.
  The corresponding output file will be the same, with the extension replaced with `html`.
  Defaults to `404.md`.
@ -71,29 +165,80 @@ The following configuration options are available:
 [custom domain]: https://docs.github.com/en/github/working-with-github-pages/managing-a-custom-domain-for-your-github-pages-site
-Available configuration options for the `[output.html.print]` table:
+### `[output.html.print]`
 The `[output.html.print]` table provides options for controlling the printable output.
 By default, mdBook will include an icon on the top right of the book (which looks like <i class="fa fa-print"></i>) that will print the book as a single page.
 ```toml
 [output.html.print]
 enable = true    # include support for printable output
 page-break = true # insert page-break after each chapter
 ```
 - **enable:** Enable print support. When `false`, all print support will not be
  rendered. Defaults to `true`.
 - **page-break** Insert page breaks between chapters. Defaults to `true`.
-Available configuration options for the `[output.html.fold]` table:
+### `[output.html.fold]`
 The `[output.html.fold]` table provides options for controlling folding of the chapter listing in the navigation sidebar.
 ```toml
 [output.html.fold]
 enable = false    # whether or not to enable section folding
 level = 0         # the depth to start folding
 ```
 - **enable:** Enable section-folding. When off, all folds are open.
  Defaults to `false`.
 - **level:** The higher the more folded regions are open. When level is 0, all
  folds are closed. Defaults to `0`.
-Available configuration options for the `[output.html.playground]` table:
+### `[output.html.playground]`
 The `[output.html.playground]` table provides options for controlling Rust sample code blocks, and their integration with the [Rust Playground].
 [Rust Playground]: https://play.rust-lang.org/
 ```toml
 [output.html.playground]
 editable = false         # allows editing the source code
 copyable = true          # include the copy button for copying code snippets
 copy-js = true           # includes the JavaScript for the code editor
 line-numbers = false     # displays line numbers for editable code
 runnable = true          # displays a run button for rust code
 ```
 - **editable:** Allow editing the source code. Defaults to `false`.
 - **copyable:** Display the copy button on code snippets. Defaults to `true`.
 - **copy-js:** Copy JavaScript files for the editor to the output directory.
  Defaults to `true`.
 - **line-numbers** Display line numbers on editable sections of code. Requires both `editable` and `copy-js` to be `true`. Defaults to `false`.
 - **runnable** Displays a run button for rust code snippets. Changing this to `false` will disable the run in playground feature globally. Defaults to `true`.
 [Ace]: https://ace.c9.io/
-Available configuration options for the `[output.html.search]` table:
+### `[output.html.search]`
 The `[output.html.search]` table provides options for controlling the built-in text [search].
 mdBook must be compiled with the `search` feature enabled (on by default).
 [search]: ../../guide/reading.md#search
 ```toml
 [output.html.search]
 enable = true            # enables the search feature
 limit-results = 30       # maximum number of search results
 teaser-word-count = 30   # number of words used for a search result teaser
 use-boolean-and = true   # multiple search terms must all match
 boost-title = 2          # ranking boost factor for matches in headers
 boost-hierarchy = 1      # ranking boost factor for matches in page names
 boost-paragraph = 1      # ranking boost factor for matches in text
 expand = true            # partial words will match longer terms
 heading-split-level = 3  # link results to heading levels
 copy-js = true           # include Javascript code for search
 ```
 - **enable:** Enables the search feature. Defaults to `true`.
 - **limit-results:** The maximum number of search results. Defaults to `30`.
@ -116,61 +261,24 @@ Available configuration options for the `[output.html.search]` table:
 - **copy-js:** Copy JavaScript files for the search implementation to the output
  directory. Defaults to `true`.
-This shows all available HTML output options in the **book.toml**:
+### `[output.html.redirect]`
 The `[output.html.redirect]` table provides a way to add redirects.
 This is useful when you move, rename, or remove a page to ensure that links to the old URL will go to the new location.
 ```toml
 [book]
 title = "Example book"
 authors = ["John Doe", "Jane Doe"]
 description = "The example book covers examples."
 [output.html]
 theme = "my-theme"
 default-theme = "light"
 preferred-dark-theme = "navy"
 curly-quotes = true
 mathjax-support = false
 copy-fonts = true
 additional-css = ["custom.css", "custom2.css"]
 additional-js = ["custom.js"]
 no-section-label = false
 git-repository-url = "https://github.com/rust-lang/mdBook"
 git-repository-icon = "fa-github"
 edit-url-template = "https://github.com/rust-lang/mdBook/edit/master/guide/{path}"
 site-url = "/example-book/"
 cname = "myproject.rs"
 input-404 = "not-found.md"
 [output.html.print]
 enable = true
 [output.html.fold]
 enable = false
 level = 0
 [output.html.playground]
 editable = false
 copy-js = true
 line-numbers = false
 [output.html.search]
 enable = true
 limit-results = 30
 teaser-word-count = 30
 use-boolean-and = true
 boost-title = 2
 boost-hierarchy = 1
 boost-paragraph = 1
 expand = true
 heading-split-level = 3
 copy-js = true
 [output.html.redirect]
 "/appendices/bibliography.html" = "https://rustc-dev-guide.rust-lang.org/appendix/bibliography.html"
 "/other-installation-methods.html" = "../infra/other-installation-methods.html"
 ```
-### Markdown Renderer
+The table contains key-value pairs where the key is where the redirect file needs to be created, as an absolute path from the build directory, (e.g. `/appendices/bibliography.html`).
 The value can be any valid URI the browser should navigate to (e.g. `https://rust-lang.org/`, `/overview.html`, or `../bibliography.html`).
 This will generate an HTML page which will automatically redirect to the given location.
 Note that the source location does not support `#` anchor redirects.
 ## Markdown Renderer
 The Markdown renderer will run preprocessors and then output the resulting
 Markdown. This is mostly useful for debugging preprocessors, especially in
@ -189,20 +297,3 @@ only whether it is enabled or disabled.
 See [the preprocessors documentation](preprocessors.md) for how to
 specify which preprocessors should run before the Markdown renderer.
 ### Custom Renderers
 A custom renderer can be enabled by adding a `[output.foo]` table to your
 `book.toml`. Similar to [preprocessors](preprocessors.md) this will
 instruct `mdbook` to pass a representation of the book to `mdbook-foo` for
 rendering. See the [alternative backends] chapter for more detail.
 The custom renderer has access to all the fields within its table (i.e.
 anything under `[output.foo]`). mdBook checks for two common fields:
 - **command:** The command to execute for this custom renderer. Defaults to
  the name of the renderer with the `mdbook-` prefix (such as `mdbook-foo`).
 - **optional:** If `true`, then the command will be ignored if it is not
  installed, otherwise mdBook will fail with an error. Defaults to `false`.
 [alternative backends]: ../../for_developers/backends.md
--- a/guide/src/format/markdown.md
+++ b/guide/src/format/markdown.md
@ -1,7 +1,7 @@
 # Markdown
-mdBook's [parser](https://github.com/raphlinus/pulldown-cmark) adheres to the [CommonMark](https://commonmark.org/)
+mdBook's [parser](https://github.com/raphlinus/pulldown-cmark) adheres to the [CommonMark](https://commonmark.org/) specification with some extensions described below.
-specification. You can take a quick [tutorial](https://commonmark.org/help/tutorial/),
+You can take a quick [tutorial](https://commonmark.org/help/tutorial/),
 or [try out](https://spec.commonmark.org/dingus/) CommonMark in real time. A complete Markdown overview is out of scope for 
 this documentation, but below is a high level overview of some of the basics. For a more in-depth experience, check out the
 [Markdown Guide](https://www.markdownguide.org).
@ -84,6 +84,20 @@ Read about [mdBook](mdBook.md).
 A bare url: <https://www.rust-lang.org>.
 ----
 Relative links that end with `.md` will be converted to the `.html` extension.
 It is recommended to use `.md` links when possible.
 This is useful when viewing the Markdown file outside of mdBook, for example on GitHub or GitLab which render Markdown automatically.
 Links to `README.md` will be converted to `index.html`.
 This is done since some services like GitHub render README files automatically, but web servers typically expect the root file to be called `index.html`.
 You can link to individual headings with `#` fragments.
 For example, `mdbook.md#text-and-paragraphs` would link to the [Text and Paragraphs](#text-and-paragraphs) section above.
 The ID is created by transforming the heading such as converting to lowercase and replacing spaces with dashes.
 You can click on any heading and look at the URL in your browser to see what the fragment looks like.
 ## Images
 Including images is simply a matter of including a link to them, much like in the _Links_ section above. The following markdown
@ -103,5 +117,106 @@ Which, of course displays the image like so:
 ![The Rust Logo](images/rust-logo-blk.svg)
 ## Extensions
-See the [Markdown Guide Basic Syntax](https://www.markdownguide.org/basic-syntax/) document for more.
+mdBook has several extensions beyond the standard CommonMark specification.
 ### Strikethrough
 Text may be rendered with a horizontal line through the center by wrapping the
 text with two tilde characters on each side:
 ```text
 An example of ~~strikethrough text~~.
 ```
 This example will render as:
 > An example of ~~strikethrough text~~.
 This follows the [GitHub Strikethrough extension][strikethrough].
 ### Footnotes
 A footnote generates a small numbered link in the text which when clicked
 takes the reader to the footnote text at the bottom of the item. The footnote
 label is written similarly to a link reference with a caret at the front. The
 footnote text is written like a link reference definition, with the text
 following the label. Example:
 ```text
 This is an example of a footnote[^note].
 [^note]: This text is the contents of the footnote, which will be rendered
    towards the bottom.
 ```
 This example will render as:
 > This is an example of a footnote[^note].
 >
 > [^note]: This text is the contents of the footnote, which will be rendered
 >     towards the bottom.
 The footnotes are automatically numbered based on the order the footnotes are
 written.
 ### Tables
 Tables can be written using pipes and dashes to draw the rows and columns of
 the table. These will be translated to HTML table matching the shape. Example:
 ```text
 | Header1 | Header2 |
 |---------|---------|
 | abc     | def     |
 ```
 This example will render similarly to this:
 | Header1 | Header2 |
 |---------|---------|
 | abc     | def     |
 See the specification for the [GitHub Tables extension][tables] for more
 details on the exact syntax supported.
 ### Task lists
 Task lists can be used as a checklist of items that have been completed.
 Example:
 ```md
 - [x] Complete task
 - [ ] Incomplete task
 ```
 This will render as:
 > - [x] Complete task
 > - [ ] Incomplete task
 See the specification for the [task list extension] for more details.
 ### Smart punctuation
 Some ASCII punctuation sequences will be automatically turned into fancy Unicode
 characters:
 | ASCII sequence | Unicode |
 |----------------|---------|
 | `--`           | –       |
 | `---`          | —       |
 | `...`          | …       |
 | `"`            | “ or ”, depending on context |
 | `'`            | ‘ or ’, depending on context |
 So, no need to manually enter those Unicode characters!
 This feature is disabled by default.
 To enable it, see the [`output.html.curly-quotes`] config option.
 [strikethrough]: https://github.github.com/gfm/#strikethrough-extension-
 [tables]: https://github.github.com/gfm/#tables-extension-
 [task list extension]: https://github.github.com/gfm/#task-list-items-extension-
 [`output.html.curly-quotes`]: configuration/renderers.md#html-renderer-options
--- a/guide/src/format/mdbook.md
+++ b/guide/src/format/mdbook.md
@ -4,6 +4,7 @@
 There is a feature in mdBook that lets you hide code lines by prepending them
 with a `#` [like you would with Rustdoc][rustdoc-hide].
 This currently only works with Rust language code blocks.
 [rustdoc-hide]: https://doc.rust-lang.org/stable/rustdoc/documentation-tests.html#hiding-portions-of-the-example
@ -27,6 +28,67 @@ Will render as
 # }
 ```
 The code block has an eyeball icon (<i class="fa fa-eye"></i>) which will toggle the visibility of the hidden lines.
 ## Rust Playground
 Rust language code blocks will automatically get a play button (<i class="fa fa-play"></i>) which will execute the code and display the output just below the code block.
 This works by sending the code to the [Rust Playground].
 ```rust
 println!("Hello, World!");
 ```
 If there is no `main` function, then the code is automatically wrapped inside one.
 If you wish to disable the play button for a code block, you can include the `noplayground` option on the code block like this:
 ~~~markdown
 ```rust,noplayground
 let mut name = String::new();
 std::io::stdin().read_line(&mut name).expect("failed to read line");
 println!("Hello {}!", name);
 ```
 ~~~
 Or, if you wish to disable the play button for all code blocks in your book, you can write the config to the `book.toml` like this.
 ```toml
 [output.html.playground]
 runnable = false
 ```
 ## Rust code block attributes
 Additional attributes can be included in Rust code blocks with comma, space, or tab-separated terms just after the language term. For example:
 ~~~markdown
 ```rust,ignore
 # This example won't be tested.
 panic!("oops!");
 ```
 ~~~
 These are particularly important when using [`mdbook test`] to test Rust examples.
 These use the same attributes as [rustdoc attributes], with a few additions:
 * `editable` — Enables the [editor].
 * `noplayground` — Removes the play button, but will still be tested.
 * `mdbook-runnable` — Forces the play button to be displayed.
  This is intended to be combined with the `ignore` attribute for examples that should not be tested, but you want to allow the reader to run.
 * `ignore` — Will not be tested and no play button is shown, but it is still highlighted as Rust syntax.
 * `should_panic` — When executed, it should produce a panic.
 * `no_run` — The code is compiled when tested, but it is not run.
  The play button is also not shown.
 * `compile_fail` — The code should fail to compile.
 * `edition2015`, `edition2018`, `edition2021` — Forces the use of a specific Rust edition.
  See [`rust.edition`] to set this globally.
 [`mdbook test`]: ../cli/test.md
 [rustdoc attributes]: https://doc.rust-lang.org/rustdoc/documentation-tests.html#attributes
 [editor]: theme/editor.md
 [`rust.edition`]: configuration/general.md#rust-options
 ## Including files
 With the following syntax, you can include files into your book:
@ -191,6 +253,17 @@ Here is what a rendered code snippet looks like:
 {{#playground example.rs}}
 Any additional values passed after the filename will be included as attributes of the code block.
 For example `\{{#playground example.rs editable}}` will create the code block like the following:
 ~~~markdown
 ```rust,editable
 # Contents of example.rs here.
 ```
 ~~~
 And the `editable` attribute will enable the [editor] as described at [Rust code block attributes](#rust-code-block-attributes).
 [Rust Playground]: https://play.rust-lang.org/
 ## Controlling page \<title\>
--- a/guide/src/format/theme/README.md
+++ b/guide/src/format/theme/README.md
@ -38,6 +38,10 @@ template and only add / modify what you need. You can copy the default theme
 into your source directory automatically by using `mdbook init --theme` and just
 remove the files you don't want to override.
 `mdbook init --theme` will not create every file listed above.
 Some files, such as `head.hbs`, do not have built-in equivalents.
 Just create the file if you need it.
 If you completely replace all built-in themes, be sure to also set
 [`output.html.preferred-dark-theme`] in the config, which defaults to the
 built-in `navy` theme.
--- a/guide/src/format/theme/editor.md
+++ b/guide/src/format/theme/editor.md
@ -12,12 +12,14 @@ editable = true
 To make a specific block available for editing, the attribute `editable` needs
 to be added to it:
-<pre><code class="language-markdown">```rust,editable
+~~~markdown
 ```rust,editable
 fn main() {
    let number = 5;
    print!("{}", number);
 }
-```</code></pre>
+```
 ~~~
 The above will result in this editable playground:
--- a/guide/src/guide/README.md
+++ b/guide/src/guide/README.md
@ -0,0 +1,7 @@
 # User Guide
 This user guide provides an introduction to basic concepts of using mdBook.
 - [Installation](installation.md)
 - [Reading Books](reading.md)
 - [Creating a Book](creating.md)
--- a/guide/src/guide/creating.md
+++ b/guide/src/guide/creating.md
@ -0,0 +1,109 @@
 # Creating a Book
 Once you have the `mdbook` CLI tool installed, you can use it to create and render a book.
 ## Initializing a book
 The `mdbook init` command will create a new directory containing an empty book for you to get started.
 Give it the name of the directory that you want to create:
 ```sh
 mdbook init my-first-book
 ```
 It will ask a few questions before generating the book.
 After answering the questions, you can change the current directory into the new book:
 ```sh
 cd my-first-book
 ```
 There are several ways to render a book, but one of the easiest methods is to use the `serve` command, which will build your book and start a local webserver:
 ```sh
 mdbook serve --open
 ```
 The `--open` option will open your default web browser to view your new book.
 You can leave the server running even while you edit the content of the book, and `mdbook` will automatically rebuild the output *and* automatically refresh your web browser.
 Check out the [CLI Guide](../cli/index.html) for more information about other `mdbook` commands and CLI options.
 ## Anatomy of a book
 A book is built from several files which define the settings and layout of the book.
 ### `book.toml`
 In the root of your book, there is a `book.toml` file which contains settings for describing how to build your book.
 This is written in the [TOML markup language](https://toml.io/).
 The default settings are usually good enough to get you started.
 When you are interested in exploring more features and options that mdBook provides, check out the [Configuration chapter](../format/configuration/index.html) for more details.
 A very basic `book.toml` can be as simple as this:
 ```toml
 [book]
 title = "My First Book"
 ```
 ### `SUMMARY.md`
 The next major part of a book is the summary file located at `src/SUMMARY.md`.
 This file contains a list of all the chapters in the book.
 Before a chapter can be viewed, it must be added to this list.
 Here's a basic summary file with a few chapters:
 ```md
 # Summary
 [Introduction](README.md)
 - [My First Chapter](my-first-chapter.md)
 - [Nested example](nested/README.md)
    - [Sub-chapter](nested/sub-chapter.md)
 ```
 Try opening up `src/SUMMARY.md` in your editor and adding a few chapters.
 If any of the chapter files do not exist, `mdbook` will automatically create them for you.
 For more details on other formatting options for the summary file, check out the [Summary chapter](../format/summary.md).
 ### Source files
 The content of your book is all contained in the `src` directory.
 Each chapter is a separate Markdown file.
 Typically, each chapter starts with a level 1 heading with the title of the chapter.
 ```md
 # My First Chapter
 Fill out your content here.
 ```
 The precise layout of the files is up to you.
 The organization of the files will correspond to the HTML files generated, so keep in mind that the file layout is part of the URL of each chapter.
 While the `mdbook serve` command is running, you can open any of the chapter files and start editing them.
 Each time you save the file, `mdbook` will rebuild the book and refresh your web browser.
 Check out the [Markdown chapter](../format/markdown.md) for more information on formatting the content of your chapters.
 All other files in the `src` directory will be included in the output.
 So if you have images or other static files, just include them somewhere in the `src` directory.
 ## Publishing a book
 Once you've written your book, you may want to host it somewhere for others to view.
 The first step is to build the output of the book.
 This can be done with the `mdbook build` command in the same directory where the `book.toml` file is located:
 ```sh
 mdbook build
 ```
 This will generate a directory named `book` which contains the HTML content of your book.
 You can then place this directory on any web server to host it.
 For more information about publishing and deploying, check out the [Continuous Integration chapter](../continuous-integration.md) for more.
--- a/guide/src/guide/installation.md
+++ b/guide/src/guide/installation.md
@ -0,0 +1,50 @@
 # Installation
 There are multiple ways to install the mdBook CLI tool.
 Choose any one of the methods below that best suit your needs.
 If you are installing mdBook for automatic deployment, check out the [continuous integration] chapter for more examples on how to install.
 [continuous integration]: ../continuous-integration.md
 ## Pre-compiled binaries
 Executable binaries are available for download on the [GitHub Releases page][releases].
 Download the binary for your platform (Windows, macOS, or Linux) and extract the archive.
 The archive contains an `mdbook` executable which you can run to build your books.
 To make it easier to run, put the path to the binary into your `PATH`.
 [releases]: https://github.com/rust-lang/mdBook/releases
 ## Build from source using Rust
 To build the `mdbook` executable from source, you will first need to install Rust and Cargo.
 Follow the instructions on the [Rust installation page].
 mdBook currently requires at least Rust version 1.54.
 Once you have installed Rust, the following command can be used to build and install mdBook:
 ```sh
 cargo install mdbook
 ```
 This will automatically download mdBook from [crates.io], build it, and install it in Cargo's global binary directory (`~/.cargo/bin/` by default).
 [Rust installation page]: https://www.rust-lang.org/tools/install
 [crates.io]: https://crates.io/
 ### Installing the latest master version
 The version published to crates.io will ever so slightly be behind the version hosted on GitHub.
 If you need the latest version you can build the git version of mdBook yourself.
 Cargo makes this ***super easy***!
 ```sh
 cargo install --git https://github.com/rust-lang/mdBook.git mdbook
 ```
 Again, make sure to add the Cargo bin directory to your `PATH`.
 If you are interested in making modifications to mdBook itself, check out the [Contributing Guide] for more information.
 [Contributing Guide]: https://github.com/rust-lang/mdBook/blob/master/CONTRIBUTING.md
--- a/guide/src/guide/reading.md
+++ b/guide/src/guide/reading.md
@ -0,0 +1,74 @@
 # Reading Books
 This chapter gives an introduction on how to interact with a book produced by mdBook.
 This assumes you are reading an HTML book.
 The options and formatting will be different for other output formats such as PDF.
 A book is organized into *chapters*.
 Each chapter is a separate page.
 Chapters can be nested into a hierarchy of sub-chapters.
 Typically, each chapter will be organized into a series of *headings* to subdivide a chapter.
 ## Navigation
 There are several methods for navigating through the chapters of a book.
 The **sidebar** on the left provides a list of all chapters.
 Clicking on any of the chapter titles will load that page.
 The sidebar may not automatically appear if the window is too narrow, particularly on mobile displays.
 In that situation, the menu icon (three horizontal bars) at the top-left of the page can be pressed to open and close the sidebar.
 The **arrow buttons** at the bottom of the page can be used to navigate to the previous or the next chapter.
 The **left and right arrow keys** on the keyboard can be used to navigate to the previous or the next chapter.
 ## Top menu bar
 The menu bar at the top of the page provides some icons for interacting with the book.
 The icons displayed will depend on the settings of how the book was generated.
 | Icon | Description |
 |------|-------------|
 | <i class="fa fa-bars"></i> | Opens and closes the chapter listing sidebar. |
 | <i class="fa fa-paint-brush"></i> | Opens a picker to choose a different color theme. |
 | <i class="fa fa-search"></i> | Opens a search bar for searching within the book. |
 | <i class="fa fa-print"></i> | Instructs the web browser to print the entire book. |
 | <i class="fa fa-github"></i> | Opens a link to the website that hosts the source code of the book. |
 | <i class="fa fa-edit"></i> | Opens a page to directly edit the source of the page you are currently reading. |
 Tapping the menu bar will scroll the page to the top.
 ## Search
 Each book has a built-in search system.
 Pressing the search icon (<i class="fa fa-search"></i>) in the menu bar, or pressing the `S` key on the keyboard will open an input box for entering search terms.
 Typing some terms will show matching chapters and sections in real time.
 Clicking any of the results will jump to that section.
 The up and down arrow keys can be used to navigate the results, and enter will open the highlighted section.
 After loading a search result, the matching search terms will be highlighted in the text.
 Clicking a highlighted word or pressing the `Esc` key will remove the highlighting.
 ## Code blocks
 mdBook books are often used for programming projects, and thus support highlighting code blocks and samples.
 Code blocks may contain several different icons for interacting with them:
 | Icon | Description |
 |------|-------------|
 | <i class="fa fa-copy"></i> | Copies the code block into your local clipboard, to allow pasting into another application. |
 | <i class="fa fa-play"></i> | For Rust code examples, this will execute the sample code and display the compiler output just below the example (see [playground]). |
 | <i class="fa fa-eye"></i> | For Rust code examples, this will toggle visibility of "hidden" lines. Sometimes, larger examples will hide lines which are not particularly relevant to what is being illustrated (see [hiding code lines]). |
 | <i class="fa fa-history"></i> | For [editable code examples][editor], this will undo any changes you have made. |
 Here's an example:
 ```rust
 println!("Hello, World!");
 ```
 [editor]: ../format/theme/editor.md
 [playground]: ../format/mdbook.md#rust-playground
 [hiding code lines]: ../format/mdbook.md#hiding-code-lines
--- a/guide/src/misc/introduction.md
+++ b/guide/src/misc/introduction.md
@ -1,3 +0,0 @@
 # Introduction
 A frontmatter chapter.
--- a/src/book/summary.rs
+++ b/src/book/summary.rs
@ -1,6 +1,6 @@
 use crate::errors::*;
 use memchr::{self, Memchr};
-use pulldown_cmark::{self, Event, Tag};
+use pulldown_cmark::{self, Event, HeadingLevel, Tag};
 use std::fmt::{self, Display, Formatter};
 use std::iter::FromIterator;
 use std::ops::{Deref, DerefMut};
@ -161,7 +161,7 @@ impl From<Link> for SummaryItem {
 /// > match the following regex: "[^<>\n[]]+".
 struct SummaryParser<'a> {
    src: &'a str,
-    stream: pulldown_cmark::OffsetIter<'a>,
+    stream: pulldown_cmark::OffsetIter<'a, 'a>,
    offset: usize,
    /// We can't actually put an event back into the `OffsetIter` stream, so instead we store it
@ -263,7 +263,7 @@ impl<'a> SummaryParser<'a> {
        loop {
            match self.next_event() {
                Some(ev @ Event::Start(Tag::List(..)))
-                | Some(ev @ Event::Start(Tag::Heading(1))) => {
+                | Some(ev @ Event::Start(Tag::Heading(HeadingLevel::H1, ..))) => {
                    if is_prefix {
                        // we've finished prefix chapters and are at the start
                        // of the numbered section.
@ -302,10 +302,10 @@ impl<'a> SummaryParser<'a> {
                    break;
                }
-                Some(Event::Start(Tag::Heading(1))) => {
+                Some(Event::Start(Tag::Heading(HeadingLevel::H1, ..))) => {
                    debug!("Found a h1 in the SUMMARY");
-                    let tags = collect_events!(self.stream, end Tag::Heading(1));
+                    let tags = collect_events!(self.stream, end Tag::Heading(HeadingLevel::H1, ..));
                    Some(stringify_events(tags))
                }
@ -375,7 +375,7 @@ impl<'a> SummaryParser<'a> {
                }
                // The expectation is that pulldown cmark will terminate a paragraph before a new
                // heading, so we can always count on this to return without skipping headings.
-                Some(ev @ Event::Start(Tag::Heading(1))) => {
+                Some(ev @ Event::Start(Tag::Heading(HeadingLevel::H1, ..))) => {
                    // we're starting a new part
                    self.back(ev);
                    break;
@ -527,15 +527,19 @@ impl<'a> SummaryParser<'a> {
    fn parse_title(&mut self) -> Option<String> {
        loop {
            match self.next_event() {
-                Some(Event::Start(Tag::Heading(1))) => {
+                Some(Event::Start(Tag::Heading(HeadingLevel::H1, ..))) => {
                    debug!("Found a h1 in the SUMMARY");
-                    let tags = collect_events!(self.stream, end Tag::Heading(1));
+                    let tags = collect_events!(self.stream, end Tag::Heading(HeadingLevel::H1, ..));
                    return Some(stringify_events(tags));
                }
                // Skip a HTML element such as a comment line.
                Some(Event::Html(_)) => {}
                // Otherwise, no title.
                Some(ev) => {
                    self.back(ev);
                    return None;
                }
                _ => return None,
            }
        }
@ -647,6 +651,18 @@ mod tests {
        assert_eq!(got, should_be);
    }
    #[test]
    fn no_initial_title() {
        let src = "[Link]()";
        let mut parser = SummaryParser::new(src);
        assert!(parser.parse_title().is_none());
        assert!(matches!(
            parser.next_event(),
            Some(Event::Start(Tag::Paragraph))
        ));
    }
    #[test]
    fn parse_title_with_styling() {
        let src = "# My **Awesome** Summary";
--- a/src/cmd/build.rs
+++ b/src/cmd/build.rs
@ -1,23 +1,29 @@
 use crate::{get_book_dir, open};
-use clap::{App, ArgMatches, SubCommand};
+use clap::{arg, App, Arg, ArgMatches};
 use mdbook::errors::Result;
 use mdbook::MDBook;
 use std::path::Path;
 // Create clap subcommand arguments
-pub fn make_subcommand<'a, 'b>() -> App<'a, 'b> {
+pub fn make_subcommand<'help>() -> App<'help> {
-    SubCommand::with_name("build")
+    App::new("build")
        .about("Builds a book from its markdown files")
-        .arg_from_usage(
+        .arg(
-            "-d, --dest-dir=[dest-dir] 'Output directory for the book{n}\
+            Arg::new("dest-dir")
-             Relative paths are interpreted relative to the book's root directory.{n}\
+                .short('d')
-             If omitted, mdBook uses build.build-dir from book.toml or defaults to `./book`.'",
+                .long("dest-dir")
                .value_name("dest-dir")
                .help(
                    "Output directory for the book{n}\
                    Relative paths are interpreted relative to the book's root directory.{n}\
                    If omitted, mdBook uses build.build-dir from book.toml or defaults to `./book`.",
                ),
        )
-        .arg_from_usage(
+        .arg(arg!([dir]
-            "[dir] 'Root directory for the book{n}\
+            "Root directory for the book{n}\
-             (Defaults to the Current Directory when omitted)'",
+            (Defaults to the Current Directory when omitted)"
-        )
+        ))
-        .arg_from_usage("-o, --open 'Opens the compiled book in a web browser'")
+        .arg(arg!(-o --open "Opens the compiled book in a web browser"))
 }
 // Build command implementation
--- a/src/cmd/clean.rs
+++ b/src/cmd/clean.rs
@ -1,23 +1,28 @@
 use crate::get_book_dir;
 use anyhow::Context;
-use clap::{App, ArgMatches, SubCommand};
+use clap::{arg, App, Arg, ArgMatches};
 use mdbook::MDBook;
 use std::fs;
 // Create clap subcommand arguments
-pub fn make_subcommand<'a, 'b>() -> App<'a, 'b> {
+pub fn make_subcommand<'help>() -> App<'help> {
-    SubCommand::with_name("clean")
+    App::new("clean")
        .about("Deletes a built book")
-        .arg_from_usage(
+        .arg(
-            "-d, --dest-dir=[dest-dir] 'Output directory for the book{n}\
+            Arg::new("dest-dir")
-             Relative paths are interpreted relative to the book's root directory.{n}\
+                .short('d')
-             Running this command deletes this directory.{n}\
+                .long("dest-dir")
-             If omitted, mdBook uses build.build-dir from book.toml or defaults to `./book`.'",
+                .value_name("dest-dir")
-        )
+                .help(
-        .arg_from_usage(
+                    "Output directory for the book{n}\
-            "[dir] 'Root directory for the book{n}\
+                    Relative paths are interpreted relative to the book's root directory.{n}\
-             (Defaults to the Current Directory when omitted)'",
+                    If omitted, mdBook uses build.build-dir from book.toml or defaults to `./book`.",
                ),
        )
        .arg(arg!([dir]
            "Root directory for the book{n}\
            (Defaults to the Current Directory when omitted)"
        ))
 }
 // Clean command implementation
--- a/src/cmd/init.rs
+++ b/src/cmd/init.rs
@ -1,5 +1,5 @@
 use crate::get_book_dir;
-use clap::{App, Arg, ArgMatches, SubCommand};
+use clap::{arg, App, Arg, ArgMatches};
 use mdbook::config;
 use mdbook::errors::Result;
 use mdbook::MDBook;
@ -8,25 +8,25 @@ use std::io::Write;
 use std::process::Command;
 // Create clap subcommand arguments
-pub fn make_subcommand<'a, 'b>() -> App<'a, 'b> {
+pub fn make_subcommand<'help>() -> App<'help> {
-    SubCommand::with_name("init")
+    App::new("init")
        .about("Creates the boilerplate structure and files for a new book")
        // the {n} denotes a newline which will properly aligned in all help messages
-        .arg_from_usage(
+        .arg(arg!([dir]
-            "[dir] 'Directory to create the book in{n}\
+            "Directory to create the book in{n}\
-             (Defaults to the Current Directory when omitted)'",
+            (Defaults to the Current Directory when omitted)"
-        )
+        ))
-        .arg_from_usage("--theme 'Copies the default theme into your source folder'")
+        .arg(arg!(--theme "Copies the default theme into your source folder"))
-        .arg_from_usage("--force 'Skips confirmation prompts'")
+        .arg(arg!(--force "Skips confirmation prompts"))
        .arg(
-            Arg::with_name("title")
+            Arg::new("title")
                .long("title")
                .takes_value(true)
                .help("Sets the book title")
                .required(false),
        )
        .arg(
-            Arg::with_name("ignore")
+            Arg::new("ignore")
                .long("ignore")
                .takes_value(true)
                .possible_values(&["none", "git"])
--- a/src/cmd/serve.rs
+++ b/src/cmd/serve.rs
@ -1,7 +1,7 @@
 #[cfg(feature = "watch")]
 use super::watch;
 use crate::{get_book_dir, open};
-use clap::{App, Arg, ArgMatches, SubCommand};
+use clap::{arg, App, Arg, ArgMatches};
 use futures_util::sink::SinkExt;
 use futures_util::StreamExt;
 use mdbook::errors::*;
@ -18,37 +18,43 @@ use warp::Filter;
 const LIVE_RELOAD_ENDPOINT: &str = "__livereload";
 // Create clap subcommand arguments
-pub fn make_subcommand<'a, 'b>() -> App<'a, 'b> {
+pub fn make_subcommand<'help>() -> App<'help> {
-    SubCommand::with_name("serve")
+    App::new("serve")
        .about("Serves a book at http://localhost:3000, and rebuilds it on changes")
        .arg_from_usage(
            "-d, --dest-dir=[dest-dir] 'Output directory for the book{n}\
             Relative paths are interpreted relative to the book's root directory.{n}\
             If omitted, mdBook uses build.build-dir from book.toml or defaults to `./book`.'",
        )
        .arg_from_usage(
            "[dir] 'Root directory for the book{n}\
             (Defaults to the Current Directory when omitted)'",
        )
        .arg(
-            Arg::with_name("hostname")
+            Arg::new("dest-dir")
-                .short("n")
+                .short('d')
                .long("dest-dir")
                .value_name("dest-dir")
                .help(
                    "Output directory for the book{n}\
                    Relative paths are interpreted relative to the book's root directory.{n}\
                    If omitted, mdBook uses build.build-dir from book.toml or defaults to `./book`.",
                ),
        )
        .arg(arg!([dir]
            "Root directory for the book{n}\
            (Defaults to the Current Directory when omitted)"
        ))
        .arg(
            Arg::new("hostname")
                .short('n')
                .long("hostname")
                .takes_value(true)
                .default_value("localhost")
-                .empty_values(false)
+                .forbid_empty_values(true)
                .help("Hostname to listen on for HTTP connections"),
        )
        .arg(
-            Arg::with_name("port")
+            Arg::new("port")
-                .short("p")
+                .short('p')
                .long("port")
                .takes_value(true)
                .default_value("3000")
-                .empty_values(false)
+                .forbid_empty_values(true)
                .help("Port to use for HTTP connections"),
        )
-        .arg_from_usage("-o, --open 'Opens the book server in a web browser'")
+        .arg(arg!(-o --open "Opens the compiled book in a web browser"))
 }
 // Serve command implementation
@ -62,11 +68,10 @@ pub fn execute(args: &ArgMatches) -> Result<()> {
    let address = format!("{}:{}", hostname, port);
    let livereload_url = format!("ws://{}/{}", address, LIVE_RELOAD_ENDPOINT);
    let update_config = |book: &mut MDBook| {
        book.config
-            .set("output.html.livereload-url", &livereload_url)
+            .set("output.html.live-reload-endpoint", &LIVE_RELOAD_ENDPOINT)
-            .expect("livereload-url update failed");
+            .expect("live-reload-endpoint update failed");
        if let Some(dest_dir) = args.value_of("dest-dir") {
            book.config.build.build_dir = dest_dir.into();
        }
--- a/src/cmd/test.rs
+++ b/src/cmd/test.rs
@ -1,29 +1,37 @@
 use crate::get_book_dir;
-use clap::{App, Arg, ArgMatches, SubCommand};
+use clap::{arg, App, Arg, ArgMatches};
 use mdbook::errors::Result;
 use mdbook::MDBook;
 // Create clap subcommand arguments
-pub fn make_subcommand<'a, 'b>() -> App<'a, 'b> {
+pub fn make_subcommand<'help>() -> App<'help> {
-    SubCommand::with_name("test")
+    App::new("test")
        .about("Tests that a book's Rust code samples compile")
-        .arg_from_usage(
+        .arg(
-            "-d, --dest-dir=[dest-dir] 'Output directory for the book{n}\
+            Arg::new("dest-dir")
-             Relative paths are interpreted relative to the book's root directory.{n}\
+                .short('d')
-             If omitted, mdBook uses build.build-dir from book.toml or defaults to `./book`.'",
+                .long("dest-dir")
                .value_name("dest-dir")
                .help(
                    "Output directory for the book{n}\
                    Relative paths are interpreted relative to the book's root directory.{n}\
                    If omitted, mdBook uses build.build-dir from book.toml or defaults to `./book`.",
                ),
        )
-        .arg_from_usage(
+        .arg(arg!([dir]
-            "[dir] 'Root directory for the book{n}\
+            "Root directory for the book{n}\
-             (Defaults to the Current Directory when omitted)'",
+            (Defaults to the Current Directory when omitted)"
-        )
+        ))
-        .arg(Arg::with_name("library-path")
+        .arg(Arg::new("library-path")
-            .short("L")
+            .short('L')
            .long("library-path")
            .value_name("dir")
            .takes_value(true)
            .use_delimiter(true)
            .require_delimiter(true)
-            .multiple(true)
+            .multiple_values(true)
-            .empty_values(false)
+            .multiple_occurrences(true)
            .forbid_empty_values(true)
            .help("A comma-separated list of directories to add to {n}the crate search path when building tests"))
 }
--- a/src/cmd/watch.rs
+++ b/src/cmd/watch.rs
@ -1,5 +1,5 @@
 use crate::{get_book_dir, open};
-use clap::{App, ArgMatches, SubCommand};
+use clap::{arg, App, Arg, ArgMatches};
 use mdbook::errors::Result;
 use mdbook::utils;
 use mdbook::MDBook;
@ -10,19 +10,25 @@ use std::thread::sleep;
 use std::time::Duration;
 // Create clap subcommand arguments
-pub fn make_subcommand<'a, 'b>() -> App<'a, 'b> {
+pub fn make_subcommand<'help>() -> App<'help> {
-    SubCommand::with_name("watch")
+    App::new("watch")
        .about("Watches a book's files and rebuilds it on changes")
-        .arg_from_usage(
+        .arg(
-            "-d, --dest-dir=[dest-dir] 'Output directory for the book{n}\
+            Arg::new("dest-dir")
-             Relative paths are interpreted relative to the book's root directory.{n}\
+                .short('d')
-             If omitted, mdBook uses build.build-dir from book.toml or defaults to `./book`.'",
+                .long("dest-dir")
                .value_name("dest-dir")
                .help(
                    "Output directory for the book{n}\
                    Relative paths are interpreted relative to the book's root directory.{n}\
                    If omitted, mdBook uses build.build-dir from book.toml or defaults to `./book`.",
                ),
        )
-        .arg_from_usage(
+        .arg(arg!([dir]
-            "[dir] 'Root directory for the book{n}\
+            "Root directory for the book{n}\
-             (Defaults to the Current Directory when omitted)'",
+            (Defaults to the Current Directory when omitted)"
-        )
+        ))
-        .arg_from_usage("-o, --open 'Open the compiled book in a web browser'")
+        .arg(arg!(-o --open "Opens the compiled book in a web browser"))
 }
 // Watch command implementation
--- a/src/config.rs
+++ b/src/config.rs
@ -533,14 +533,14 @@ pub struct HtmlConfig {
    /// directly jumping to editing the currently viewed page.
    /// Contains {path} that is replaced with chapter source file path
    pub edit_url_template: Option<String>,
-    /// This is used as a bit of a workaround for the `mdbook serve` command.
+    /// Endpoint of websocket, for livereload usage. Value loaded from .toml file
-    /// Basically, because you set the websocket port from the command line, the
+    /// is ignored, because our code overrides this field with the value [`LIVE_RELOAD_ENDPOINT`]
-    /// `mdbook serve` command needs a way to let the HTML renderer know where
+    ///
-    /// to point livereloading at, if it has been enabled.
+    /// [`LIVE_RELOAD_ENDPOINT`]: cmd::serve::LIVE_RELOAD_ENDPOINT
    ///
    /// This config item *should not be edited* by the end user.
    #[doc(hidden)]
-    pub livereload_url: Option<String>,
+    pub live_reload_endpoint: Option<String>,
    /// The mapping from old pages to new pages/URLs to use when generating
    /// redirects.
    pub redirect: HashMap<String, String>,
@ -569,7 +569,7 @@ impl Default for HtmlConfig {
            input_404: None,
            site_url: None,
            cname: None,
-            livereload_url: None,
+            live_reload_endpoint: None,
            redirect: HashMap::new(),
        }
    }
@ -588,15 +588,20 @@ impl HtmlConfig {
 /// Configuration for how to render the print icon, print.html, and print.css.
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
-#[serde(rename_all = "kebab-case")]
+#[serde(default, rename_all = "kebab-case")]
 pub struct Print {
    /// Whether print support is enabled.
    pub enable: bool,
    /// Insert page breaks between chapters. Default: `true`.
    pub page_break: bool,
 }
 impl Default for Print {
    fn default() -> Self {
-        Self { enable: true }
+        Self {
            enable: true,
            page_break: true,
        }
    }
 }
@ -625,6 +630,8 @@ pub struct Playground {
    pub copy_js: bool,
    /// Display line numbers on playground snippets. Default: `false`.
    pub line_numbers: bool,
    /// Display the run button. Default: `true`
    pub runnable: bool,
 }
 impl Default for Playground {
@ -634,6 +641,7 @@ impl Default for Playground {
            copyable: true,
            copy_js: true,
            line_numbers: false,
            runnable: true,
        }
    }
 }
@ -776,6 +784,7 @@ mod tests {
            copyable: true,
            copy_js: true,
            line_numbers: false,
            runnable: true,
        };
        let html_should_be = HtmlConfig {
            curly_quotes: true,
@ -806,6 +815,22 @@ mod tests {
        assert_eq!(got.html_config().unwrap(), html_should_be);
    }
    #[test]
    fn disable_runnable() {
        let src = r#"
        [book]
        title = "Some Book"
        description = "book book book"
        authors = ["Shogo Takata"]
        [output.html.playground]
        runnable = false
        "#;
        let got = Config::from_str(src).unwrap();
        assert_eq!(got.html_config().unwrap().playground.runnable, false);
    }
    #[test]
    fn edition_2015() {
        let src = r#"
@ -1150,4 +1175,24 @@ mod tests {
        Config::from_str(src).unwrap();
    }
    #[test]
    fn print_config() {
        let src = r#"
        [output.html.print]
        enable = false
        "#;
        let got = Config::from_str(src).unwrap();
        let html_config = got.html_config().unwrap();
        assert_eq!(html_config.print.enable, false);
        assert_eq!(html_config.print.page_break, true);
        let src = r#"
        [output.html.print]
        page-break = false
        "#;
        let got = Config::from_str(src).unwrap();
        let html_config = got.html_config().unwrap();
        assert_eq!(html_config.print.enable, true);
        assert_eq!(html_config.print.page_break, false);
    }
 }
--- a/src/main.rs
+++ b/src/main.rs
@ -5,7 +5,8 @@ extern crate log;
 use anyhow::anyhow;
 use chrono::Local;
-use clap::{App, AppSettings, Arg, ArgMatches, Shell, SubCommand};
+use clap::{App, AppSettings, Arg, ArgMatches};
 use clap_complete::Shell;
 use env_logger::Builder;
 use log::LevelFilter;
 use mdbook::utils;
@ -25,25 +26,31 @@ fn main() {
    // Check which subcomamnd the user ran...
    let res = match app.get_matches().subcommand() {
-        ("init", Some(sub_matches)) => cmd::init::execute(sub_matches),
+        Some(("init", sub_matches)) => cmd::init::execute(sub_matches),
-        ("build", Some(sub_matches)) => cmd::build::execute(sub_matches),
+        Some(("build", sub_matches)) => cmd::build::execute(sub_matches),
-        ("clean", Some(sub_matches)) => cmd::clean::execute(sub_matches),
+        Some(("clean", sub_matches)) => cmd::clean::execute(sub_matches),
        #[cfg(feature = "watch")]
-        ("watch", Some(sub_matches)) => cmd::watch::execute(sub_matches),
+        Some(("watch", sub_matches)) => cmd::watch::execute(sub_matches),
        #[cfg(feature = "serve")]
-        ("serve", Some(sub_matches)) => cmd::serve::execute(sub_matches),
+        Some(("serve", sub_matches)) => cmd::serve::execute(sub_matches),
-        ("test", Some(sub_matches)) => cmd::test::execute(sub_matches),
+        Some(("test", sub_matches)) => cmd::test::execute(sub_matches),
-        ("completions", Some(sub_matches)) => (|| {
+        Some(("completions", sub_matches)) => (|| {
            let shell: Shell = sub_matches
                .value_of("shell")
                .ok_or_else(|| anyhow!("Shell name missing."))?
                .parse()
                .map_err(|s| anyhow!("Invalid shell: {}", s))?;
-            create_clap_app().gen_completions_to("mdbook", shell, &mut std::io::stdout().lock());
+            let mut complete_app = create_clap_app();
            clap_complete::generate(
                shell,
                &mut complete_app,
                "mdbook",
                &mut std::io::stdout().lock(),
            );
            Ok(())
        })(),
-        (_, _) => unreachable!(),
+        _ => unreachable!(),
    };
    if let Err(e) = res {
@ -54,14 +61,13 @@ fn main() {
 }
 /// Create a list of valid arguments and sub-commands
-fn create_clap_app<'a, 'b>() -> App<'a, 'b> {
+fn create_clap_app() -> App<'static> {
    let app = App::new(crate_name!())
        .about(crate_description!())
        .author("Mathieu David <mathieudavid@mathieudavid.org>")
        .version(VERSION)
-        .setting(AppSettings::GlobalVersion)
+        .setting(AppSettings::PropagateVersion)
        .setting(AppSettings::ArgRequiredElseHelp)
        .setting(AppSettings::ColoredHelp)
        .after_help(
            "For more information about a specific command, try `mdbook <command> --help`\n\
             The source code for mdBook is available at: https://github.com/rust-lang/mdBook",
@ -71,12 +77,12 @@ fn create_clap_app<'a, 'b>() -> App<'a, 'b> {
        .subcommand(cmd::test::make_subcommand())
        .subcommand(cmd::clean::make_subcommand())
        .subcommand(
-            SubCommand::with_name("completions")
+            App::new("completions")
                .about("Generate shell completions for your shell to stdout")
                .arg(
-                    Arg::with_name("shell")
+                    Arg::new("shell")
                        .takes_value(true)
-                        .possible_values(&Shell::variants())
+                        .possible_values(Shell::possible_values())
                        .help("the shell to generate completions for")
                        .value_name("SHELL")
                        .required(true),
@ -137,3 +143,8 @@ fn open<P: AsRef<OsStr>>(path: P) {
        error!("Error opening web browser: {}", e);
    }
 }
 #[test]
 fn verify_app() {
    create_clap_app().debug_assert();
 }
--- a/src/renderer/html_handlebars/hbs_renderer.rs
+++ b/src/renderer/html_handlebars/hbs_renderer.rs
@ -56,7 +56,7 @@ impl HtmlHandlebars {
        let fixed_content =
            utils::render_markdown_with_path(&ch.content, ctx.html_config.curly_quotes, Some(path));
-        if !ctx.is_index {
+        if !ctx.is_index && ctx.html_config.print.page_break {
            // Add page break between chapters
            // See https://developer.mozilla.org/en-US/docs/Web/CSS/break-before and https://developer.mozilla.org/en-US/docs/Web/CSS/page-break-before
            // Add both two CSS properties because of the compatibility issue
@ -170,6 +170,13 @@ impl HtmlHandlebars {
        // Set a dummy path to ensure other paths (e.g. in the TOC) are generated correctly
        data_404.insert("path".to_owned(), json!("404.md"));
        data_404.insert("content".to_owned(), json!(html_content_404));
        let mut title = String::from("Page not found");
        if let Some(book_title) = &ctx.config.book.title {
            title.push_str(" - ");
            title.push_str(book_title);
        }
        data_404.insert("title".to_owned(), json!(title));
        let rendered = handlebars.render("index", &data_404)?;
        let rendered =
@ -606,8 +613,11 @@ fn make_data(
    if theme.favicon_svg.is_some() {
        data.insert("favicon_svg".to_owned(), json!("favicon.svg"));
    }
-    if let Some(ref livereload) = html_config.livereload_url {
+    if let Some(ref live_reload_endpoint) = html_config.live_reload_endpoint {
-        data.insert("livereload".to_owned(), json!(livereload));
+        data.insert(
            "live_reload_endpoint".to_owned(),
            json!(live_reload_endpoint),
        );
    }
    let default_theme = match html_config.default_theme {
@ -768,16 +778,7 @@ fn insert_link_into_header(
    content: &str,
    id_counter: &mut HashMap<String, usize>,
 ) -> String {
-    let raw_id = utils::id_from_content(content);
+    let id = utils::unique_id_from_content(content, id_counter);
    let id_count = id_counter.entry(raw_id.clone()).or_insert(0);
    let id = match *id_count {
        0 => raw_id,
        other => format!("{}-{}", raw_id, other),
    };
    *id_count += 1;
    format!(
        r##"<h{level} id="{id}"><a class="header" href="#{id}">{text}</a></h{level}>"##,
@ -828,7 +829,8 @@ fn add_playground_pre(
            if classes.contains("language-rust") {
                if (!classes.contains("ignore")
                    && !classes.contains("noplayground")
-                    && !classes.contains("noplaypen"))
+                    && !classes.contains("noplaypen")
                    && playground_config.runnable)
                    || classes.contains("mdbook-runnable")
                {
                    let contains_e2015 = classes.contains("edition2015");
--- a/src/renderer/html_handlebars/search.rs
+++ b/src/renderer/html_handlebars/search.rs
@ -97,9 +97,10 @@ fn render_item(
    breadcrumbs.push(chapter.name.clone());
    let mut id_counter = HashMap::new();
    while let Some(event) = p.next() {
        match event {
-            Event::Start(Tag::Heading(i)) if i <= max_section_depth => {
+            Event::Start(Tag::Heading(i, ..)) if i as u32 <= max_section_depth => {
                if !heading.is_empty() {
                    // Section finished, the next heading is following now
                    // Write the data to the index, and clear it for the next section
@ -118,9 +119,9 @@ fn render_item(
                in_heading = true;
            }
-            Event::End(Tag::Heading(i)) if i <= max_section_depth => {
+            Event::End(Tag::Heading(i, ..)) if i as u32 <= max_section_depth => {
                in_heading = false;
-                section_id = Some(utils::id_from_content(&heading));
+                section_id = Some(utils::unique_id_from_content(&heading, &mut id_counter));
                breadcrumbs.push(heading.clone());
            }
            Event::Start(Tag::FootnoteDefinition(name)) => {
--- a/src/theme/index.hbs
+++ b/src/theme/index.hbs
@ -219,10 +219,12 @@
        </div>
-        {{#if livereload}}
+        {{#if live_reload_endpoint}}
        <!-- Livereload script (if served using the cli tool) -->
        <script type="text/javascript">
-            var socket = new WebSocket("{{{livereload}}}");
+            const wsProtocol = location.protocol === 'https:' ? 'wss:' : 'ws:';
            const wsAddress = wsProtocol + "//" + location.host + "/" + "{{{live_reload_endpoint}}}";
            const socket = new WebSocket(wsAddress);
            socket.onmessage = function (event) {
                if (event.data === "reload") {
                    socket.close();
--- a/src/utils/mod.rs
+++ b/src/utils/mod.rs
@ -9,6 +9,7 @@ use regex::Regex;
 use pulldown_cmark::{html, CodeBlockKind, CowStr, Event, Options, Parser, Tag};
 use std::borrow::Cow;
 use std::collections::HashMap;
 use std::fmt::Write;
 use std::path::Path;
@ -44,6 +45,8 @@ pub fn normalize_id(content: &str) -> String {
 /// Generate an ID for use with anchors which is derived from a "normalised"
 /// string.
 // This function should be made private when the deprecation expires.
 #[deprecated(since = "0.4.16", note = "use unique_id_from_content instead")]
 pub fn id_from_content(content: &str) -> String {
    let mut content = content.to_string();
@ -59,10 +62,30 @@ pub fn id_from_content(content: &str) -> String {
    // Remove spaces and hashes indicating a header
    let trimmed = content.trim().trim_start_matches('#').trim();
    normalize_id(trimmed)
 }
 /// Generate an ID for use with anchors which is derived from a "normalised"
 /// string.
 ///
 /// Each ID returned will be unique, if the same `id_counter` is provided on
 /// each call.
 pub fn unique_id_from_content(content: &str, id_counter: &mut HashMap<String, usize>) -> String {
    let id = {
        #[allow(deprecated)]
        id_from_content(content)
    };
    // If we have headers with the same normalized id, append an incrementing counter
    let id_count = id_counter.entry(id.clone()).or_insert(0);
    let unique_id = match *id_count {
        0 => id,
        id_count => format!("{}-{}", id, id_count),
    };
    *id_count += 1;
    unique_id
 }
 /// Fix links to the correct location.
 ///
 /// This adjusts links, such as turning `.md` extensions to `.html`.
@ -160,7 +183,7 @@ pub fn render_markdown(text: &str, curly_quotes: bool) -> String {
    render_markdown_with_path(text, curly_quotes, None)
 }
-pub fn new_cmark_parser(text: &str, curly_quotes: bool) -> Parser<'_> {
+pub fn new_cmark_parser(text: &str, curly_quotes: bool) -> Parser<'_, '_> {
    let mut opts = Options::empty();
    opts.insert(Options::ENABLE_TABLES);
    opts.insert(Options::ENABLE_FOOTNOTES);
@ -332,8 +355,9 @@ more text with spaces
        }
    }
-    mod html_munging {
+    #[allow(deprecated)]
-        use super::super::{id_from_content, normalize_id};
+    mod id_from_content {
        use super::super::id_from_content;
        #[test]
        fn it_generates_anchors() {
@ -361,6 +385,10 @@ more text with spaces
            );
            assert_eq!(id_from_content("## Über"), "Über");
        }
    }
    mod html_munging {
        use super::super::{normalize_id, unique_id_from_content};
        #[test]
        fn it_normalizes_ids() {
@ -379,5 +407,28 @@ more text with spaces
            assert_eq!(normalize_id("한국어"), "한국어");
            assert_eq!(normalize_id(""), "");
        }
        #[test]
        fn it_generates_unique_ids_from_content() {
            // Same id if not given shared state
            assert_eq!(
                unique_id_from_content("## 中文標題 CJK title", &mut Default::default()),
                "中文標題-cjk-title"
            );
            assert_eq!(
                unique_id_from_content("## 中文標題 CJK title", &mut Default::default()),
                "中文標題-cjk-title"
            );
            // Different id if given shared state
            let mut id_counter = Default::default();
            assert_eq!(unique_id_from_content("## Über", &mut id_counter), "Über");
            assert_eq!(
                unique_id_from_content("## 中文標題 CJK title", &mut id_counter),
                "中文標題-cjk-title"
            );
            assert_eq!(unique_id_from_content("## Über", &mut id_counter), "Über-1");
            assert_eq!(unique_id_from_content("## Über", &mut id_counter), "Über-2");
        }
    }
 }
--- a/tests/cli/build.rs
+++ b/tests/cli/build.rs
@ -1,7 +1,6 @@
 use crate::cli::cmd::mdbook_cmd;
 use crate::dummy_book::DummyBook;
 use assert_cmd::Command;
 #[test]
 fn mdbook_cli_dummy_book_generates_index_html() {
    let temp = DummyBook::new().build().unwrap();
@ -9,7 +8,7 @@ fn mdbook_cli_dummy_book_generates_index_html() {
    // doesn't exist before
    assert!(!temp.path().join("book").exists());
-    let mut cmd = Command::cargo_bin("mdbook").unwrap();
+    let mut cmd = mdbook_cmd();
    cmd.arg("build").current_dir(temp.path());
    cmd.assert()
        .success()
--- a/tests/cli/cmd.rs
+++ b/tests/cli/cmd.rs
@ -0,0 +1,7 @@
 use assert_cmd::Command;
 pub(crate) fn mdbook_cmd() -> Command {
    let mut cmd = Command::cargo_bin("mdbook").unwrap();
    cmd.env_remove("RUST_LOG");
    cmd
 }
--- a/tests/cli/mod.rs
+++ b/tests/cli/mod.rs
@ -1,2 +1,3 @@
 mod build;
 mod cmd;
 mod test;
--- a/tests/cli/test.rs
+++ b/tests/cli/test.rs
@ -1,13 +1,13 @@
 use crate::cli::cmd::mdbook_cmd;
 use crate::dummy_book::DummyBook;
 use assert_cmd::Command;
 use predicates::boolean::PredicateBooleanExt;
 #[test]
 fn mdbook_cli_can_correctly_test_a_passing_book() {
    let temp = DummyBook::new().with_passing_test(true).build().unwrap();
-    let mut cmd = Command::cargo_bin("mdbook").unwrap();
+    let mut cmd = mdbook_cmd();
    cmd.arg("test").current_dir(temp.path());
    cmd.assert().success()
      .stderr(predicates::str::is_match(r##"Testing file: "([^"]+)[\\/]README.md""##).unwrap())
@ -22,7 +22,7 @@ fn mdbook_cli_can_correctly_test_a_passing_book() {
 fn mdbook_cli_detects_book_with_failing_tests() {
    let temp = DummyBook::new().with_passing_test(false).build().unwrap();
-    let mut cmd = Command::cargo_bin("mdbook").unwrap();
+    let mut cmd = mdbook_cmd();
    cmd.arg("test").current_dir(temp.path());
    cmd.assert().failure()
      .stderr(predicates::str::is_match(r##"Testing file: "([^"]+)[\\/]README.md""##).unwrap())
--- a/tests/dummy_book/src/SUMMARY.md
+++ b/tests/dummy_book/src/SUMMARY.md
@ -13,6 +13,7 @@
    - [Markdown](first/markdown.md)
    - [Unicode](first/unicode.md)
    - [No Headers](first/no-headers.md)
    - [Duplicate Headers](first/duplicate-headers.md)
 - [Second Chapter](second.md)
    - [Nested Chapter](second/nested.md)
--- a/tests/dummy_book/src/first/duplicate-headers.md
+++ b/tests/dummy_book/src/first/duplicate-headers.md
@ -0,0 +1,9 @@
 # Duplicate headers
 This page validates behaviour of duplicate headers.
 # Header Text
 # Header Text
 # header-text
--- a/tests/rendered_output.rs
+++ b/tests/rendered_output.rs
@ -17,6 +17,7 @@ use std::ffi::OsStr;
 use std::fs;
 use std::io::Write;
 use std::path::{Component, Path, PathBuf};
 use std::str::FromStr;
 use tempfile::Builder as TempFileBuilder;
 use walkdir::{DirEntry, WalkDir};
@ -35,6 +36,7 @@ const TOC_SECOND_LEVEL: &[&str] = &[
    "1.4. Markdown",
    "1.5. Unicode",
    "1.6. No Headers",
    "1.7. Duplicate Headers",
    "2.1. Nested Chapter",
 ];
@ -150,6 +152,25 @@ fn rendered_code_has_playground_stuff() {
    assert_contains_strings(book_js, &[".playground"]);
 }
 #[test]
 fn rendered_code_does_not_have_playground_stuff_in_html_when_disabled_in_config() {
    let temp = DummyBook::new().build().unwrap();
    let config = Config::from_str(
        "
    [output.html.playground]
    runnable = false
    ",
    )
    .unwrap();
    let md = MDBook::load_with_config(temp.path(), config).unwrap();
    md.build().unwrap();
    let nested = temp.path().join("book/first/nested.html");
    let playground_class = vec![r#"class="playground""#];
    assert_doesnt_contain_strings(nested, &playground_class);
 }
 #[test]
 fn anchors_include_text_between_but_not_anchor_comments() {
    let temp = DummyBook::new().build().unwrap();
@ -633,11 +654,12 @@ mod search {
        let some_section = get_doc_ref("first/index.html#some-section");
        let summary = get_doc_ref("first/includes.html#summary");
        let no_headers = get_doc_ref("first/no-headers.html");
        let duplicate_headers_1 = get_doc_ref("first/duplicate-headers.html#header-text-1");
        let conclusion = get_doc_ref("conclusion.html#conclusion");
        let bodyidx = &index["index"]["index"]["body"]["root"];
        let textidx = &bodyidx["t"]["e"]["x"]["t"];
-        assert_eq!(textidx["df"], 2);
+        assert_eq!(textidx["df"], 5);
        assert_eq!(textidx["docs"][&first_chapter]["tf"], 1.0);
        assert_eq!(textidx["docs"][&introduction]["tf"], 1.0);
@ -646,7 +668,7 @@ mod search {
        assert_eq!(docs[&some_section]["body"], "");
        assert_eq!(
            docs[&summary]["body"],
-            "Dummy Book Introduction First Chapter Nested Chapter Includes Recursive Markdown Unicode No Headers Second Chapter Nested Chapter Conclusion"
+            "Dummy Book Introduction First Chapter Nested Chapter Includes Recursive Markdown Unicode No Headers Duplicate Headers Second Chapter Nested Chapter Conclusion"
        );
        assert_eq!(
            docs[&summary]["breadcrumbs"],
@ -657,6 +679,10 @@ mod search {
            docs[&no_headers]["breadcrumbs"],
            "First Chapter » No Headers"
        );
        assert_eq!(
            docs[&duplicate_headers_1]["breadcrumbs"],
            "First Chapter » Duplicate Headers » Header Text"
        );
        assert_eq!(
            docs[&no_headers]["body"],
            "Capybara capybara capybara. Capybara capybara capybara."
--- a/tests/searchindex_fixture.json
+++ b/tests/searchindex_fixture.json