Tachyony: Imported page

2021-12-06T15:57:21Z

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{{hatnote|If you are looking for help finding factual information about people, places, things, or events, leave a message at [[Wikipedia:Reference desk]]. To get help finding out how to use Wikipedia, leave a note at [[Wikipedia:Help desk]].}}
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{{redirect-distinguish|Wikipedia:Article history|Template:Article history}}
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[[File:View History- marked screenshot.png|thumb|250px|If you want to view a page's history, go to the page (e.g., [[Cat]]) and click the "[[Special:PageHistory/Cat|View history]]" tab in the upper-right section of the screen.]]
[[File:Using the view history tab on Wikipedia.webm|thumb|250px|10-minute video introduction to the View History feature.]]

A '''page history''' shows the order in which edits were made to any editable [[Wikipedia]] page, the difference between any two revisions, and a menu of special external tools. A page history is sometimes called '''revision history''' or '''edit history'''.

You can view a page's history by clicking the “View history” tab at the top of the associated page (''pictured right'').

The page history contains a list of the page's previous revisions, including the date and time—in [[w:UTC|UTC]] by default—of each edit, the [[Help:Username|username]] or [[IP address]] of the user who made the change, and an optional [[Help:Edit summary|edit summary]] that briefly describes or explains the change. For example, the [[Special:PageHistory/Help:Page history|page history]] for this help page shows that it was first created on September 20, 2004, and that it has been changed more than 500 times since then.

==External tools on "page history" pages==
On every "page history" page, before the history begins, there are links to several external tools for analyzing or correcting a page. On Wikipedia, these are:
* Find addition/removal calls a tool called [[Wikipedia:WikiBlame|WikiBlame]], which searches page histories (not the body of pages) for [[String (computer science)|strings]], reporting which user(s) were responsible for adding or deleting the string.
* Find edits by user.
* Page statistics gives word, character, and link counts, top editors, and edit counts by month and year. "Page information", in every page's left-hand margin, gives highlights of this information.
* Page views over any time period selected. "Page information", in the left-hand margin, gives page views for the previous 30 days only.
* Fix dead links. Dead links will be repaired if the page linked has been archived in the [[Internet Archive]]. Repairs will generate an entry in the "page history".
** On the dead links tool, there is a box which, if checked, will cause the tool to back up in the Internet Archive those linked pages not yet in it. This is not needed (and is sometimes blocked) for major sources like [[The New York Times]], but is valuable for pages which are more likely to go dead, such as personal pages and those from small businesses and small or temporary organizations.

== Using a history page ==
===Overview===
On a history page:
* All past changes to the page in question are listed in reverse-chronological order.
* To view a specific revision, click a date.
* To compare an old revision with the current revision, go to the old revision, click '''cur'''.
* To compare a revision with its predecessor, click '''prev'''.
* To compare two specific revisions, click the left-column radio button of the older revision and the right-column radio button of the newer revision, and then click the "Compare selected revisions" button.
* To undo (revert) your own or someone else's edit, click the "undo" link. See [[Wikipedia:Undo]] for more information.

Below is a detailed example of a page history using the default skin:

[[File:MediaWiki 1.21wmf3 page history screenshot.svg|900px]]

Edits are shown from newest to oldest. Each edit takes up one line which shows; time and date, the contributor's username or [[IP address]] and the [[Help:Edit summary|edit summary]], as well as other diagnostic information.
Let's look at some of the functions of this page:
# The "View history" tab is highlighted and "Revision history" is appended to the page name. Notice that you can't make [[Help:Link|wikilinks]] to this extended page name – to make a link to the history page, copy the [[URL]] from the browser address bar when viewing the history page, and paste it between ''single'' square brackets (external link format) to make the link. {{tl|History}} can also be used.
# The year and month fields allow a quick jump when the page has many revisions. After entering a year and/or selecting a month, click the "Go" button to the right.
# The "[[Wikipedia:Tags|Tag]] filter" restricts the display to show only those edits that have been tagged by an [[WP:Edit filter|edit filter]]. For example, "references removed" may be entered here. After entering a tag name, click the "Go" button to the right.
# The "Deleted only" checkbox is only shown to [[Wikipedia:Administrators|administrators]] and others with the <code>deletedhistory</code> [[Wikipedia:User access levels|user right]]. It displays [[Wikipedia:Revision deletion|RevisionDeleted]] edits.
# A line of links to external tools.<ref group=note>Shown in the screenshot, above, are:
* <code>Find addition/removal</code> ([[WP:WIKIBLAME|Wikiblame]], allows you to find the person who wrote or deleted a given passage of text),
* <code>Find edits by user</code> (find all the edits a particular user made to the page),
* <code>Page statistics</code> (lists all people who have edited the page, from most contributions made to least; a graph of when edits were made; and other statistics.),
* <code>Pageviews</code> (shows a graph of how many people accessed the page over time and reports how many people have the page on their [[Help:Watching pages|watchlist]]),
* <code>Fix dead links</code> (offers tools to analyze web pages and fix links).
These are external links to sites that host the tools off-site, such as [[WP:Toolserver|Toolserver]] or the newer [[WP:WMFLabs|Labs]].</ref> The available tools vary between wikis. The line is made by [[MediaWiki:Histlegend]] which can be edited by administrators.
# These links take you to the most recent edits ''(latest)'', oldest edits ''(earliest)'' or the next or previous page of edits ''(newer n / older n)''. Note that the black text in brackets will become links, when applicable.
# The blue numbers list the number of edits displayed on a page - 20, 50, 100, 250 or 500. A higher number increases the length of a page, but reduces the number of pages. The number you select replaces ''n'' in the links to the previous or next pages e.g. ''(newer 100 / older 100)''.
# ''(cur)'' takes you to a [[Help:diff|diff]] page, showing the difference between that edit and the current revision. The current revision appears below the changes, so you can see how the page is now rendered.
# ''(prev)'' takes you to a diff page showing the changes between that edit and the previous revision. The most recent revision (the one on the same line as the "prev" you clicked on) appears below the changes, so you can see how the page was rendered.
# The two columns of [[w:radio button|radio buttons]] can be used to select any two revisions on the page. The current selection is marked by a special background. The two most recent revisions are selected by default when you first view the history (that is why they appear framed and have a different background, see horizontal area below 4). Let's say you want to compare the revisions corresponding to numbers 10 & 11 on the image. First, click the left radio button next to number 11. The right column of buttons will then fill as far as number 11. Then click the right button next to number 10. Finally, click ''Compare selected revisions''. This takes you to a diff page showing the changes between the two revisions. The most recent revision (in this case number 10) appears below the changes, so you can see how the page was rendered.
# This gives the time and date of the edit. The time is [[UTC]] by default at the English Wikipedia. Registered users can choose date format and time zone at [[Special:Preferences#mw-prefsection-rendering]]. The date and time contains a link to that revision of the page. Thus the first line links to the revision that was current at the time of loading this revision history, and therefore the result may differ from that of following the link on the page margin to the current revision. Even if the page has not changed in the meantime, the {{msg|Revision-info}} appears.
# The username or IP of the contributor appears here.
# '''m''' stands for [[Help:minor edit|minor edit]].
# The size of the page in bytes (roughly corresponding to characters)
# The difference in size between this revision and the previous revision. A green number with a plus sign <span class='mw-plusminus-pos'>(+1,864)</span> indicates that the edit added this number of bytes (roughly corresponding to characters) to the page, while a red number with a minus sign <span class='mw-plusminus-neg'>(-29)</span> indicates removal. See more at [[Wikipedia:Added or removed characters]].
# This is the [[Help:edit summary|edit summary]]. It is the text the user wrote in the edit summary box (below the edit box).
# This edit summary begins with an arrow link and grey text. This means the user has only edited a section of the page (named in the grey text). This text is automatically added when you edit a section. The arrow links to that section of the current revision of the page, and not the revision where the arrow was clicked. A standard edit summary can be added by the user. This appears in black text.

Not shown in this example: some edits may be automatically [[Wikipedia:Tags|tagged]] by the abuse filter (example: <code>''(Tag: references removed)''</code>); any tags applied appear after the edit summary. Tags cannot be added or removed manually, and are intended to help editors identify potential problem edits for examination; they do not ''prove'' that an edit is problematic.

Also not shown in this example: you can thank a user for their edit by clicking the Thank button. see [[Wikipedia:Notifications/Thanks]].

It is possible to restore an old revision of a page by following the link to that revision, clicking "edit" and then saving. This should be done with caution, as it means that ''all'' changes made to the page since the time of that revision will be undone.

In rare cases, all or part of a page history entry may be shown in grey, struck out by a horizontal line. This indicates that information has been hidden from public view by an administrator. See [[Wikipedia:Revision deletion|Revision deletion]] and [[Wikipedia:Oversight|Oversight]] for more on this.

===Searching and exporting histories===
The history page contains a link "Find addition/removal". This links to [http://wikipedia.ramselehof.de/wikiblame.php Wikiblame], a tool for searching the entire history of a given page.

Another useful tool is the [[Special:Export]] page, which is used to produce an [[XML]] file with the wikitext of the current and (optionally) all old revisions of one or more specified pages, with date, time, username, and edit summary. How the XML file is displayed depends on the browser (it can also be saved locally for later searching and analysis). For more information on this feature, see [[Help:Export]].

The following may also be useful:
* https://xtools.wmflabs.org/articleinfo/index.php? – a tool to sort the page history by editor and count the number of edits for each editor (works for most Wikimedia sites; can also be downloaded for adaptation to other MediaWiki sites).
* [[Wikipedia:Usemod article histories]] – information on retrieving page histories from before January 2002.
* [[meta:Community Tech/Who Wrote That tool]] – a tool to highlight contributions by each editor on a page

Some page histories (such as [[User talk:Jimbo Wales]]) are very long, so that paging back even 500 results at a time cannot practically reach a date from several years ago. It is possible to simply change the date (YYYYMMDD) in the URL in these cases ( <code><nowiki>http://en.wikipedia.org/w/index.php?title=User_talk:Jimbo_Wales&offset=</nowiki>'''20061215'''<nowiki>142129&action=history</nowiki></code>, for example) to get a listing of results going back from that date.

===Web feeds===
A link to an Atom [[WP:Syndication|web feed]] for the history of a page is available from the lefthand <code>Toolbox</code>. This gives the [[Help:diff|diffs]] of the last 10 edits, each with a link to the ordinary, full diff page. Depending on the browser there may be possibilities such as sorting by author.

An RSS version of the feed can be obtained by assigning to "feed" (one of the {{mlmw|Manual:Parameters_to_index.php|History|parameters to index.php available for a history page}}) the value "rss", i.e., by replacing "&feed=atom" with "&feed=rss" in the Atom feed link.

==Related issues==
===Moved and deleted pages===
When a page is [[Help:Moving a page|moved]] (renamed), the entire edit history of the article, before and after the move, is shown. The old title becomes a [[Help:redirect|redirect]] and loses its edit history.

To view a history of only moves and no other edits, go to [[special:log/move]] and input the name of the article in the "target" field.

If instead of a move, the entire content was [[Cut, copy, and paste|cut, copied, and paste]]d into a new substitute article, the page history gets spread across two articles. The histories can be [[Wikipedia:How to fix cut-and-paste moves|merged]] in this case.

When two pages are merged, typically one becomes a redirect. In this case, the revision history of the redirect is kept.

When a page is deleted, its revision history remains in the database and can be retrieved by an administrator, who can also undelete the page (see [[Wikipedia:Viewing and restoring deleted pages]]).

Administrators can also remove selected revisions from a page history, for example if they contain defamatory text. For details, see [[Wikipedia:Selective deletion|Selective deletion]].

===Image histories===
An "image" (in the broad sense of an uploaded file) can be edited, or, more generally, be replaced by a different image, by uploading a new image file with the same name. Again, all revisions are kept. The image history listing forms part of the [[Help:Image description page|image description page]], which appears when clicking on the image. The image history consists of this and the old revisions themselves.

Images which have been deleted from their source are only available to administrators (not to be confused with images removed from an article but not from their source), so the only record available is the upload log, deletion log and possibly the "votes for deletion" archive. Only administrators can restore a deleted image without uploading it again.

===Linking to a specific revision of a page===
{{Shortcut|H:PHLINK|WP:OLDID|WP:PAGEHISTLINK}}
It is sometimes useful to link to a specific revision of an article — this is called a "[[Help:Permanent link|permanent link]]". For example, one might have done a review of a Wikipedia article and want to indicate which particular revision was reviewed.

[[File:Permalink.jpg|thumb|right|Getting a link to an older revision of a page]]
A permanent link to the current revision of an article is normally available from the sidebar, under Tools ⇒ Permanent link. For other [[WP:Namespace|namespaces]], or if the revision to be linked to is not the current revision, use the page's History tab to navigate to the specific revision required. The URL here will be suitable for use to permanently reference this revision, and can usually be obtained from the browser's location bar. (See also [[Help:URL#URLs of Wikipedia pages|URLs of Wikipedia pages]].) To make a permalink for use within the English Wikipedia, use [[Template:Oldid2]].

A permalink does not necessarily reproduce the historical revision of the page as it originally appeared. This is because images, [[WP:Template|templates]] (transcluded text and images), and time-based variables (such as <nowiki>CURRENTTIME</nowiki>) may have changed in the interim; they appear in their current state, not their historical state. Only the on-page text of the article (the wikitext that one sees when clicking 'Edit') is preserved perfectly.

===Copyright status of old page revisions===

Those wishing to make use of historical revisions of articles should be aware that some of the history may be problematic.

As noted at the end of each history revision, in the text at [[MediaWiki:history copyright]], the page histories may contain material that is incompatible with our license. Although all contributions are supposed to be compatible with CC BY-SA (except limited, clearly marked fair use material in accordance with our [[Wikipedia:Non-free content|non-free content policy]]), it is possible that a user has inserted something to which they did not have rights to license or which exceeds fair use. The Wikipedia volunteer community has a general policy of removing such copyright problems from publication when they are discovered (see [[wikipedia:copyright problems|copyright problems]]), but does not have a general policy of always deleting all such material from the history, particularly if the edit is made to an existing article rather than a new one. In the event of a [[Digital Millennium Copyright Act|DMCA]] takedown notice, the Wikimedia Foundation may remove violating revisions from the page history. In other cases, the revision may be kept to allow proper tracking of authors and demonstrate compliance with all legal requirements. As the Wikimedia Foundation is a not-for-profit company, the volunteer community believes this to be fair use. However, not all revisions in a page history are necessarily available under the CC BY-SA.

=== Very old revisions ===
{{main|Wikipedia:Wikipedia's oldest articles}}
Revision history for most pages prior to 2001 is not available.

==See also==
{{Wikipedia glossary}}
* [[Template:Oldid2]], link to an old revision of a page
* [[Template:Cross-wiki language oldid]], link to an old revision of a page in Wikibooks, Wikinews, Wikiquote, Wikisource, Wikiversity, or Wiktionary in any language
* [[Template:Cross-wiki oldid]], link to an old revision of a page in MediaWiki, Meta-Wiki, Wikibooks, Wikimedia Foundation, Wikimedia Incubator, Wikinews, Wikiquote, Wikisource, Wikiversity, or Wiktionary
* [[Help:Diff]]
* [[Help:User contributions]]
* Watch this video "Using the "view history" tab on Wikipedia" [https://www.youtube.com/watch?v=Y45CQtdMK1w instructional video] by Pete Forsyth from a WP course
* [https://cosmiclattes.github.io/wikireplay/player.html Wiki RePlay]: A JavaScript tool to visualize diffs in Wikipedia. Enter the name of the page in the "page". There is a slider showing the revisions, click on one of the bars in the zoomed in revision of the revisions to start the playback
* [[Wikipedia:Help desk/Archives/2018 April 16#Tech problem in history pages]]

==Notes==
{{Reflist|group=note}}

{{Wikipedia technical help|collapsed}}

[[Category:Wikipedia page history| ]]
[[Category:Wikipedia page history help| ]]
[[Category:Wikipedia interface help|History tab]]

Help:Page history - Revision history

Tachyony: Imported page