MD013 - Line length

Tags: line_length

Aliases: line-length Parameters: linelength, codeblocks, tables (number; default 80, boolean; default true)

This rule is triggered when there are lines that are longer than the configured line length (default: 80 characters). To fix this, split the line up into multiple lines.

This rule has an exception where there is no whitespace beyond the configured line length. This allows you to still include items such as long URLs without being forced to break them in the middle.

You also have the option to exclude this rule for code blocks and tables. To do this, set the code_blocks and/or tables parameters to false.

Code blocks are included in this rule by default since it is often a requirement for document readability, and tentatively compatible with code rules. Still, some languages do not lend themselves to short lines.

MD013 - Line length

Tags: line_length

Aliases: line-length Parameters: linelength, codeblocks, tables (number; default 80, boolean; default true)

This rule is triggered when there are lines that are longer than the configured line length (default: 80 characters). To fix this, split the line up into multiple lines.

This rule has an exception where there is no whitespace beyond the configured line length. This allows you to still include items such as long URLs without being forced to break them in the middle.

You also have the option to exclude this rule for code blocks and tables. To do this, set the code_blocks and/or tables parameters to false.

Code blocks are included in this rule by default since it is often a requirement for document readability, and tentatively compatible with code rules. Still, some languages do not lend themselves to short lines.

MD026 - Trailing punctuation in header

Tags: headers

Aliases: no-trailing-punctuation

Parameters: punctuation (string; default ".,;:!?")

This rule is triggered on any header that has a punctuation character as the last character in the line:

# This is a header.

To fix this, remove any trailing punctuation:

# This is a header

Note: The punctuation parameter can be used to specify what characters class as punctuation at the end of the header. For example, you can set it to '.,;:!' to allow headers with question marks in them, such as might be used in an FAQ.

MD002 - First header should be a top level header

Tags: headers

Aliases: first-header-h1

Parameters: level (number; default 1)

This rule is triggered when the first header in the document isn't a h1 header:

## This isn't a H1 header

### Another header

The first header in the document should be a h1 header:

# Start with a H1 header

## Then use a H2 for subsections

MD013 - Line length

Tags: line_length

Aliases: line-length Parameters: linelength, codeblocks, tables (number; default 80, boolean; default true)

This rule is triggered when there are lines that are longer than the configured line length (default: 80 characters). To fix this, split the line up into multiple lines.

This rule has an exception where there is no whitespace beyond the configured line length. This allows you to still include items such as long URLs without being forced to break them in the middle.

You also have the option to exclude this rule for code blocks and tables. To do this, set the code_blocks and/or tables parameters to false.

Code blocks are included in this rule by default since it is often a requirement for document readability, and tentatively compatible with code rules. Still, some languages do not lend themselves to short lines.

MD013 - Line length

Tags: line_length

Aliases: line-length Parameters: linelength, codeblocks, tables (number; default 80, boolean; default true)

This rule is triggered when there are lines that are longer than the configured line length (default: 80 characters). To fix this, split the line up into multiple lines.

This rule has an exception where there is no whitespace beyond the configured line length. This allows you to still include items such as long URLs without being forced to break them in the middle.

You also have the option to exclude this rule for code blocks and tables. To do this, set the code_blocks and/or tables parameters to false.

Code blocks are included in this rule by default since it is often a requirement for document readability, and tentatively compatible with code rules. Still, some languages do not lend themselves to short lines.

MD001 - Header levels should only increment by one level at a time

Tags: headers

Aliases: header-increment

This rule is triggered when you skip header levels in a markdown document, for example:

# Header 1

### Header 3

We skipped out a 2nd level header in this document

When using multiple header levels, nested headers should increase by only one level at a time:

# Header 1

## Header 2

### Header 3

#### Header 4

## Another Header 2

### Another Header 3

MD009 - Trailing spaces

Tags: whitespace

Aliases: no-trailing-spaces

Parameters: br_spaces (number; default: 0)

This rule is triggered on any lines that end with whitespace. To fix this, find the line that is triggered and remove any trailing spaces from the end.

The brspaces parameter allows an exception to this rule for a specific amount of trailing spaces used to insert an explicit line break/br element. For example, set brspaces to 2 to allow exactly 2 spaces at the end of a line.

Note: you have to set brspaces to 2 or higher for this exception to take effect - you can't insert a br element with just a single trailing space, so if you set brspaces to 1, the exception will be disabled, just as if it was set to the default of 0.

MD009 - Trailing spaces

Tags: whitespace

Aliases: no-trailing-spaces

Parameters: br_spaces (number; default: 0)

This rule is triggered on any lines that end with whitespace. To fix this, find the line that is triggered and remove any trailing spaces from the end.

The brspaces parameter allows an exception to this rule for a specific amount of trailing spaces used to insert an explicit line break/br element. For example, set brspaces to 2 to allow exactly 2 spaces at the end of a line.

Note: you have to set brspaces to 2 or higher for this exception to take effect - you can't insert a br element with just a single trailing space, so if you set brspaces to 1, the exception will be disabled, just as if it was set to the default of 0.

MD013 - Line length

Tags: line_length

Aliases: line-length Parameters: linelength, codeblocks, tables (number; default 80, boolean; default true)

This rule is triggered when there are lines that are longer than the configured line length (default: 80 characters). To fix this, split the line up into multiple lines.

This rule has an exception where there is no whitespace beyond the configured line length. This allows you to still include items such as long URLs without being forced to break them in the middle.

You also have the option to exclude this rule for code blocks and tables. To do this, set the code_blocks and/or tables parameters to false.

Code blocks are included in this rule by default since it is often a requirement for document readability, and tentatively compatible with code rules. Still, some languages do not lend themselves to short lines.

MD013 - Line length

Tags: line_length

Aliases: line-length Parameters: linelength, codeblocks, tables (number; default 80, boolean; default true)

This rule is triggered when there are lines that are longer than the configured line length (default: 80 characters). To fix this, split the line up into multiple lines.

This rule has an exception where there is no whitespace beyond the configured line length. This allows you to still include items such as long URLs without being forced to break them in the middle.

You also have the option to exclude this rule for code blocks and tables. To do this, set the code_blocks and/or tables parameters to false.

Code blocks are included in this rule by default since it is often a requirement for document readability, and tentatively compatible with code rules. Still, some languages do not lend themselves to short lines.

MD018 - No space after hash on atx style header

Tags: headers, atx, spaces

Aliases: no-missing-space-atx

This rule is triggered when spaces are missing after the hash characters in an atx style header:

#Header 1

##Header 2

To fix this, separate the header text from the hash character by a single space:

# Header 1

## Header 2

MD018 - No space after hash on atx style header

Tags: headers, atx, spaces

Aliases: no-missing-space-atx

This rule is triggered when spaces are missing after the hash characters in an atx style header:

#Header 1

##Header 2

To fix this, separate the header text from the hash character by a single space:

# Header 1

## Header 2

MD022 - Headers should be surrounded by blank lines

Tags: headers, blank_lines

Aliases: blanks-around-headers

This rule is triggered when headers (any style) are either not preceded or not followed by a blank line:

# Header 1
Some text

Some more text
## Header 2

To fix this, ensure that all headers have a blank line both before and after (except where the header is at the beginning or end of the document):

# Header 1

Some text

Some more text

## Header 2

Rationale: Aside from aesthetic reasons, some parsers, including kramdown, will not parse headers that don't have a blank line before, and will parse them as regular text.

MD024 - Multiple headers with the same content

Tags: headers

Aliases: no-duplicate-header

Parameters: allowdifferentnesting (boolean; default false)

This rule is triggered if there are multiple headers in the document that have the same text:

# Some text

## Some text

To fix this, ensure that the content of each header is different:

# Some text

## Some more text

Rationale: Some markdown parses generate anchors for headers based on the header name, and having headers with the same content can cause problems with this.

If the parameter allow_different_nesting is set to true, header duplication under different nesting is allowed, like it usually happens in change logs:

# Change log

## 2.0.0

### Bug fixes

### Features

## 1.0.0

### Bug fixes

MD032 - Lists should be surrounded by blank lines

Tags: bullet, ul, ol, blank_lines

Aliases: blanks-around-lists

This rule is triggered when lists (of any kind) are either not preceded or not followed by a blank line:

Some text
* Some
* List

1. Some
2. List
Some text

To fix this, ensure that all lists have a blank line both before and after (except where the block is at the beginning or end of the document):

Some text

* Some
* List

1. Some
2. List

Some text

Rationale: Aside from aesthetic reasons, some parsers, including kramdown, will not parse lists that don't have blank lines before and after them.

Note: List items without hanging indents are a violation of this rule; list items with hanging indents are okay:

* This is
not okay

* This is
  okay

MD033 - Inline HTML

Tags: html

Aliases: no-inline-html

This rule is triggered whenever raw HTML is used in a markdown document:

Inline HTML header

To fix this, use 'pure' markdown instead of including raw HTML:

# Markdown header

Rationale: Raw HTML is allowed in markdown, but this rule is included for those who want their documents to only include "pure" markdown, or for those who are rendering markdown documents in something other than HTML.

MD033 - Inline HTML

Tags: html

Aliases: no-inline-html

This rule is triggered whenever raw HTML is used in a markdown document:

Inline HTML header

To fix this, use 'pure' markdown instead of including raw HTML:

# Markdown header

Rationale: Raw HTML is allowed in markdown, but this rule is included for those who want their documents to only include "pure" markdown, or for those who are rendering markdown documents in something other than HTML.

MD013 - Line length

Tags: line_length

Aliases: line-length Parameters: linelength, codeblocks, tables (number; default 80, boolean; default true)

This rule is triggered when there are lines that are longer than the configured line length (default: 80 characters). To fix this, split the line up into multiple lines.

This rule has an exception where there is no whitespace beyond the configured line length. This allows you to still include items such as long URLs without being forced to break them in the middle.

You also have the option to exclude this rule for code blocks and tables. To do this, set the code_blocks and/or tables parameters to false.

Code blocks are included in this rule by default since it is often a requirement for document readability, and tentatively compatible with code rules. Still, some languages do not lend themselves to short lines.

MD030 - Spaces after list markers

Tags: ol, ul, whitespace

Aliases: list-marker-space

Parameters: ulsingle, olsingle, ulmulti, olmulti (number, default 1)

This rule checks for the number of spaces between a list marker (e.g. '-', '*', '+' or '1.') and the text of the list item.

The number of spaces checked for depends on the document style in use, but the default is 1 space after any list marker:

* Foo
* Bar
* Baz

1. Foo
1. Bar
1. Baz

1. Foo
   * Bar
1. Baz

A document style may change the number of spaces after unordered list items and ordered list items independently, as well as based on whether the content of every item in the list consists of a single paragraph, or multiple paragraphs (including sub-lists and code blocks).

For example, the style guide at http://www.cirosantilli.com/markdown-styleguide/#spaces-after-marker specifies that 1 space after the list marker should be used if every item in the list fits within a single paragraph, but to use 2 or 3 spaces (for ordered and unordered lists respectively) if there are multiple paragraphs of content inside the list:

* Foo
* Bar
* Baz

vs.

*   Foo

    Second paragraph

*   Bar

or

1.  Foo

    Second paragraph

1.  Bar

To fix this, ensure the correct number of spaces are used after list marker for your selected document style.