Help:Magic words

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It explains concepts or processes used by the Wikipedia community. It is not one of Wikipedia's policies or guidelines, and may reflect varying levels of consensus.

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Magic words (including parser functions, variables, and behavior switches) are features of wiki markup that give instructions to Wikipedia's underlying MediaWiki software. For example, magic words can suppress or position the table of contents, disable indexing by external search engines, and produce output dynamically based on the current page or on user-defined conditional logic. Some of these features are especially useful for templates.

This page is a quick reference for magic words. For more information, refer to the main MediaWiki documentation:

mw:Help:Magic words: All standard magic words, including the "standard" parser functions.
mw:Help:Extension:ParserFunctions: Additional parser functions, including conditional expressions.

General information

In general, there are three types of magic words.

Behavior switches: often appear in double underscores, all uppercase, e.g., __NOTOC__. They will change the behavior of a page, rather than return a value.
Parser functions: all in lowercase. A parser function will be followed by colon and pipe-separated parameters, e.g., {{#ifexpr:Y|Yes|No}}, wrapped in double braces. They will take a value and return a value.
Variables: these are all uppercase, e.g., {{PAGENAME}}. A variable will be wrapped in double braces and will return a value in its place.

The software generally interprets magic words in the following way:

Magic words are case sensitive.
White space is generously allowed for readability. It will be stripped from the start and end of their keywords and parameters (as is also done in template calls using named parameters).
They can be transcluded, even variables "about the current page". This is ensured by the parsing order.
Instead of magically transforming into HTML instructions, <nowiki> tags remove this magic so a magic word can itself be displayed (documented), e.g. <nowiki>{{#magic:}}</nowiki>or {{#magic:<nowiki/>}}.

Magic words compared to templates:

As with templates, magic words can be transcluded and substituted.
The names of magic words are purposely chosen to be unlike the names of templates, and vice versa. Many parser function names will begin with a #(pound or hash), but template names will not start with a #, and probably not end in a :(colon), or be all-uppercase.
The first parameter's syntax differs. In {{#magic: p1 | p2 | p3}}, the name is #magicand it is followed by an unspaced :and a required input parameter, p1. With a template, p1is optional and it is preceded by a |(pipe) instead of a :, e.g. {{template|p1}}.

Most magic words can be used in any needed locations on a page; see MOS:ORDER for guidance on where Wikipedia prefers to place some magic words that are behavior switches (examples: DEFAULTSORT and DISPLAYTITLE).

Behavior switches

Variables

Shortcut

WP:VAR

Note: The magic words above can also take a parameter, in order to parse values on a page other than the current page. A colon (:) is used to pass the parameter, rather than a pipe (|) that is used in templates, like {{MAGICWORD:value}}. For example, {{TALKPAGENAME:Wikipedia:MOS}} returns Wikipedia talk:MOS on any page.

Caution: Attempting to use (some) page name variables to create a wikilink to an image page, category page or interlanguage link will produce a different effect: this will respectively place the image on the page, add the page to the category, or create an interlanguage link at the edge of the page. To override this normal behavior, prefix the variable with a colon (:); for example [[:{{FULLPAGENAME}}]].

For more details on parser functions that relate to page names and namespaces, see: meta:Help:Page name § Variables and parser functions.

Other variables by type

Parser functions

Shortcuts

Metadata

Page IDs can be associated with articles via wikilinks (i.e. Special:Redirect/page/3235121goes to this page). To output numbers without comma separators (for example, as "123456789" rather than "123,456,789"), append the parameter |R.

Formatting

Paths

Conditional

If, in these conditional functions, empty unnamed parameters are to be parsed as empty rather than as text (i.e. as empty rather than as the text "{{{1}}}", "{{{2}}}", etc.), they will require trailing pipes (i.e. {{{1|}}}, {{{2|}}}, etc., rather than {{{1}}}, {{{2}}}, etc.).

For the use of these functions in tables, see Help:Conditional tables.

Other

Substituting and nesting

Magic words can sometimes behave weirdly when substituted or nested. It's possible to subst some magic words (so that the page stops being updated if the value of the word changes). Here are some examples of how this works:

Notes