Editing Help:Diff (section)

==Linking to a diff==
{{For|Linking to an old version of a page|Help:Permlink}}
If you need to create a link to a specific diff (for use on a talk page or noticeboard, for example), it is best to use the <nowiki>[[</nowiki>Special:Diff/<var><code>oldid</code></var><nowiki>]]</nowiki> method or {{Tl|Diff}}, which make links work across protocols (<code>http://</code> vs. <code>https://</code>) and on our mobile site. Alternatively, locate the diff from the [[Help:Page history|page history]], go to the diff page, and copy the [[URL]] from your browser's address bar. You can paste this URL (the whole of it, including <nowiki>https://</nowiki>) into the text of the page where you want the link to appear, putting single square brackets [...] around it.

=== External links ===
The URL for a diff is based on the <code>oldid</code> value of the old revision. If a revision has oldid value 12345678, its URL is:
*<code><nowiki>https://en.wikipedia.org/w/index.php?title=PAGETITLE&oldid=12345678</nowiki></code>

You can strip the <code>title=PAGETITLE&</code> part from the URL and make it look like this:
*<code><nowiki>https://en.wikipedia.org/w/index.php?oldid=12345678</nowiki></code>

Then URLs for its diffs may take the forms:

*Diff with the current version:<br/><code><nowiki>https://en.wikipedia.org/w/index.php?diff=cur&oldid=123456789</nowiki></code>
*Diff with the previous version:<br/><code><nowiki>https://en.wikipedia.org/w/index.php?diff=prev&oldid=123456789</nowiki></code>
*Diff with version 10000001:<br/><code><nowiki>https://en.wikipedia.org/w/index.php?diff=100000001&oldid=123456789</nowiki></code>
*To show only a diff and not the page content, add <code>&diffonly=1</code> to any of the above:<br/><code><nowiki>https://en.wikipedia.org/w/index.php?diff=cur&oldid=123456789&diffonly=1</nowiki></code>

A shorter alternative to link to the diff with the previous version is:
*<code><nowiki>https://en.wikipedia.org/wiki/?diff=12345678</nowiki></code>

=== Internal links ===
Although external links are easy to copy and paste, they can be long and unwieldy. Diffs can be wikilinked using <nowiki>[[</nowiki>Special:Diff/<var><code>diff</code></var><nowiki>]]</nowiki> (e.g. [[Special:Diff/123456789]]) or <nowiki>[[</nowiki>Special:Diff/<var><code>oldid</code></var>/<var><code>diff</code></var><nowiki>]]</nowiki> (e.g. [[Special:Diff/100000001/123456789]]) where you should replace <var><code>oldid</code></var> and <var><code>diff</code></var> with appropriate values seen in the URL. This syntax is easy and can even be used in [[WP:EDSUM|edit summaries]].

=== <nowiki>{{Diff}}</nowiki> or <nowiki>{{Diff2}}</nowiki> ===
Using {{tl|diff}} or {{T|diff2}} is another approach of linking to a diff within Wikipedia, though it cannot be used in edit summaries. The general syntax is:
:{{tlx|Diff|<var>page</var>|<var>diff</var>|<var>oldid</var>|<var>label</var>}}
*{{para|<var>page</var>}}&nbsp;– The title of the page.
*{{para|<var>diff</var>}}&nbsp;– The ID or keyword that is used against the base ID. Possible keywords are:
**<kbd>cur</kbd>&nbsp;– compare with the current (latest) version of a page.
**<kbd>prev</kbd>&nbsp;– compare with the previous version of a page.
**<kbd>next</kbd>&nbsp;– compare with the next version of a page.
**<var>id</var>&nbsp;– This should be {{em|larger}} than <code>oldid</code>.
*{{para|<var>oldid</var>}}&nbsp;– The base ID onto which the diff is generated.
*{{para|<var>label</var>}}&nbsp;– Text to display as link. No label will give a numbered link.
*{{para|diffonly|yes}}&nbsp;– Shows only a diff and not the page content.  Parameter name required.

==== <nowiki>{{URL to diff}}</nowiki> ====

{{Tl|URL to diff}} takes a full diff URL and converts it to a {{Tl|Diff}} template. The template should be substituted, thus:

:<code><nowiki>{{Subst:URL to diff|url=https://en.wikipedia.org/w/index.php?diff=100000001&oldid=123456789|label=relevant text}}</nowiki></code>