Tomblog603

1. Md Syntax Underline
2. Github Md Syntax
3. Md File Syntax

Markdown is a lightweight and easy-to-use syntax for styling all forms of writing on the GitHub platform.

What you will learn:

• How the Markdown format makes styled collaborative editing easy
• How Markdown differs from traditional formatting approaches
• How to use Markdown to format text
• How to leverage GitHub’s automatic Markdown rendering
• How to apply GitHub’s unique Markdown extensions

Absolute links such as /src/api.md are resolved relative to the top of the enclosing Git repository, but within the same branch or Git commit. Links may point to any file in the repository. A link to a.md file will present the rendered markdown, while a link to a source file will display the syntax highlighted source. MD is back with his second solo EP and the whole thing is brilliant again! Check out this collab with Koherent which is also part of it. Out tomorrow on Prog.

Learn Markdown by creating a README.md file in GitHub, and manually translate a Word document into it. While emulating th rich text of a Word document, we l. You can use other Markdown syntax inside blockquotes; Blockquote. Nested blockquote. Code comments Inline. Enclose the text in backticks `code`Inline code looks like this sentence; Code blocks. Indent a block by four spaces; MD vs MDX. MDX is a superset of Markdown. It allows you to write JSX inside markdown. Narrow: Markdown is a an easy-to use, lightweight markup language with syntax that maximizes readability and ergonomics while writing and makes publishing for the web super easy. It was created by John Gruber and Aaron Swartz, and is now used on thousands of websites and inside some of the world's most popular open source projects.

What is Markdown?

Markdown is a way to style text on the web. You control the display of the document; formatting words as bold or italic, adding images, and creating lists are just a few of the things we can do with Markdown. Mostly, Markdown is just regular text with a few non-alphabetic characters thrown in, like # or *.

You can use Markdown most places around GitHub:

• Comments in Issues and Pull Requests
• Files with the .md or .markdown extension

For more information, see “Writing on GitHub” in the GitHub Help.

Examples

Syntax guide

Here’s an overview of Markdown syntax that you can use anywhere on GitHub.com or in your own text files.

Headers

Emphasis

Lists

Unordered

Ordered

Images

Links

Blockquotes

Inline code

GitHub Flavored Markdown

GitHub.com uses its own version of the Markdown syntax that provides an additional set of useful features, many of which make it easier to work with content on GitHub.com.

Note that some features of GitHub Flavored Markdown are only available in the descriptions and comments of Issues and Pull Requests. These include @mentions as well as references to SHA-1 hashes, Issues, and Pull Requests. Task Lists are also available in Gist comments and in Gist Markdown files.

Syntax highlighting

Here’s an example of how you can use syntax highlighting with GitHub Flavored Markdown:

You can also simply indent your code by four spaces:

Here’s an example of Python code without syntax highlighting:

Md Syntax Underline

Task Lists

If you include a task list in the first comment of an Issue, you will get a handy progress indicator in your issue list. It also works in Pull Requests!

Tables

You can create tables by assembling a list of words and dividing them with hyphens - (for the first row), and then separating each column with a pipe |:

Would become:

SHA references

Any reference to a commit’s SHA-1 hash will be automatically converted into a link to that commit on GitHub.

Issue references within a repository

Any number that refers to an Issue or Pull Request will be automatically converted into a link.

Username @mentions

Typing an @ symbol, followed by a username, will notify that person to come and view the comment. This is called an “@mention”, because you’re mentioning the individual. You can also @mention teams within an organization.

Automatic linking for URLs

Any URL (like http://www.github.com/) will be automatically converted into a clickable link.

Strikethrough

Any word wrapped with two tildes (like ~~this~~) will appear crossed out.

Emoji

GitHub supports emoji!

To see a list of every image we support, check out the Emoji Cheat Sheet.

Last updated Jan 15, 2014

Summary

This module manages common properties of domains for one or more virtual hosts. Its serves two main purposes: for one, supervise/renew TLS certificates via the ACME protocol (RFC 8555). Certificates will be renewed by the module ahead of their expiration to account for disruption in internet services. There are ways to monitor the status of all certififcates managed this way and configurations that will run your own notification commands on renewal, expiration and errors.

Second, mod_md offers an alternate OCSP Stapling implementation. This works with managed certificates as well as with certificates you configure yourself. OCSP Stapling is a necessary component for any https: site, influencing page load times and, depending on other setups, page availability. More in the stapling section below.

The default ACME Authority for managing certificates is Let's Encrypt, but it is possible to configure another CA that supports the protocol.

Simple configuration example:

TLS in a VirtualHost context

This setup will, on server start, contact Let's Encrypt to request a certificate for the domain. If Let's Encrypt can verify the ownership of the domain, the module will retrieve the certificate and its chain, store it in the local file system (see MDStoreDir) and provide it, on next restart, to mod_ssl.

This happens while the server is already running. All other hosts will continue to work as before. While a certificate is not available, requests for the managed domain will be answered with a '503 Service Unavailable'.

Prerequisites

This module requires mod_watchdog to be loaded as well.

Certificate sign-up and renewal with Let's Encrypt requires your server to be reachable on port 80 (http:) and/or port 443 (https:) from the public internet. (Unless your server is configured to use DNS for challenges - more on that under 'wildcard certificates')

The module will select from the methods offered by Let's Encrypt. Usually LE offers challenges on both ports and DNS and Apache chooses a method available.

To determine which one is available, the module looks at the ports Apache httpd listens on. If those include port 80, it assumes that the http: challenge (named http-01) is available. If the server listens on port 443, the https: challenge (named tls-alpn-01) is also added to the list. (And if MDChallengeDns01 is configured, the challenge dns-01 is added as well.)

If your setup is not so straight forward, there are two methods available to influence this. First, look at MDPortMap if the server is behind a portmapper, such as a firewall. Second, you may override the module's guesswork completely by configuring MDCAChallenges directly.

https: Challenges

For domain verification via the TLS protocol `tls-alpn-01` is the name of the challenge type. It requires the Apache server to listen on port 443 (see MDPortMap if you map that port to something else).

Let's Encrypt will open a TLS connection to Apache using the special indicator `acme-tls/1` (this indication part of TLS is called ALPN, therefore the name of the challenge. ALPN is also used by browsers to request a HTTP/2 connection).

As with the HTTP/2 protocol, to allow this, you configure:

And the `tls-alpn-01` challenge type is available.

Wildcard Certificates

Wildcard certificates are possible, but not straight-forward to use out of the box. Let's Encrypt requires the `dns-01` challenge verification for those. No other is considered good enough.

The difficulty here is that Apache cannot do that on its own. As the name implies, `dns-01` requires you to show some specific DNS records for your domain that contain some challenge data. So you need to _write_ your domain's DNS records.

If you know how to do that, you can integrated this with mod_md. Let's say you have a script for that in `/usr/bin/acme-setup-dns` you configure Apache with:

and Apache will call this script when it needs to setup/teardown a DNS challenge record for a domain.

Assuming you want a certificate for `*.mydomain.com`, mod_md will call:

and afterwards it will call

Monitoring

Apache has a standard module for monitoring: mod_status. mod_md contributes a section and makes monitoring your domains easy.

You see all your MDs listed alphabetically, the domain names they contain, an overall status, expiration times and specific settings. The settings show your selection of renewal times (or the default), the CA that is used, etc.

The 'Renewal' column will show activity and error descriptions for certificate renewals. This should make life easier for people to find out if everything is all right or what went wrong.

If there is an error with an MD it will be shown here as well. This let's you assess problems without digging through your server logs.

There is also a new 'md-status' handler available to give you the MD information from 'server-status' in JSON format. You configure it as

on your server. As with 'server-status' you will want to add authorization for this.

If you just want to check the JSON status of a specific domain, simply append that to your status url:

This JSON status also shows a log of activities when domains are renewed:

You will also find this information in the file `job.json` in your staging and, when activated, domains directory. This allows you to inspect these at any later point in time as well.

In addition, there is MDCertificateStatus which gives access to relevant certificate information in JSON format.

Stapling

If you want to try the stapling in one Managed Domain alone at first, configure:

and use the 'server-status' and/or MDMessageCmd to see how it operates. You will see if Stapling information is there, how long it is valid, from where it came and when it will be refreshed.

If this all works to your satisfaction, you can switch it on for all your certificates or just your managed ones.

Github Md Syntax

The existing stapling implementation by mod_ssl is used by many sites for years. There are two main differences between the mod_ssl and mod_md one:

1. On demand vs. scheduled: mod_ssl retrieves the stapling information when it is requested, e.g. on a new connection. mod_md retrieves it right at server start and after 2/3rds of its lifetime.
2. In memory vs. persisted: mod_ssl can persist this information, but most example configurations use a memory cache. mod_md always stores in the file system.

Md File Syntax

If you are unlucky and restart your server during an outage of your CA's OCSP service, your users may no longer reach your sites. Without persistence your server cannot provide the client with the data and the client browser cannot get it as well, since the OCSP service is not responding.

The implementation in mod_md will have peristed it, load it again after restart and have it available for incoming connections. A day or two before this information expires, it will renew it, making it able to copy with a long OCSP service downtime.

Due to backward compatibility, the existing implementation in mod_ssl could not be changed drastically. For example, mod_ssl is unable to add a dependency to mod_watchdog without braking many existing installations (that do not load it).