Help:Page History

General Overview
The revision history, also called page history or edit history, of all pages is available. It consists of the old versions of the wikitext, and also a record of the date and time of every edit, the user who made it, the edit summary, and a possible marking as "minor edit".

Page history
Every page has a link "Page history" to the list of edits. Also the Recent changes and Related changes pages have links to the histories of listed pages.

An exception are pages which have been deleted (not to be confused with pages that have been blanked), for which the only record available to non-administrators is the deletion log and possibly the "votes for deletion" archive. Edits to them are not even in the User Contributions pages.

Every line represents one edit to the given page and the version resulting from it
 * "last" is similar to "diff", explained in Recent changes
 * "cur" gives the difference between this version and the one at the time of loading the history page (i.e., excluding the edit shown by pressing the "last" next to it), which is the cumulation of all later edits, except those which are not in this revision history because they were made after loading this page
 * the date and time link to the version of that day and time, using a URL with oldid=revisionid.

For every version there is a box on the line. Marking two boxes gives the difference between the two versions. The box at the top corresponds to the latest edit, which is not necessarily the edit about which the info on the line is (another edit may have been made after loading the page history),

If the "move page" feature has been used in the past to change the name to the current one, the entire edit history of the article, before and after the move, is shown, but the move itself is not. The move itself is shown in the edit history of the page with the old title, which automatically has become a redirect page.

After merging two pages, typically one becomes a redirect. In that case, this redirect has a real edit history.

Reverting a page
If your new pages edits aren't to your liking, don't panic, you can 'revert' the page to any previous version using this technique ->

Providing for a separate edit history for a section
Without changing the appearance of a page, a section of it can be an included separate page, see composite pages. This way a separate edit history is provided for the section. Also this allows watching it separately.

Permalink; history of the wikitext vs. history of the rendered page
It is occasionally useful to link to a specific version of an article (a snapshot of it). For example, one might have done a review of a Wikipedia article and want to indicate which particular version was reviewed.

If the version is not the current version, one can use the page history to view the old version of the page. The URL of this old version is suitable for use to permanently reference this version, and can usually be obtained from the browser's location bar.

If the version is the current version, for technical reasons it is impossible to link to that specific version. The best solution is to make some change to the page (ideally an improvement, but a change that has no effect on the rendered form of the page is probably easier) so that the version of interest is no longer current, then follow the instructions above.

See also URLs of old versions of pages.

The history of the wikitext should not be confused with the history of the rendered page:


 * If a page contains a variable depending on time, its rendered content varies with time; for example, gives the time of viewing the page; if at some stage the tag  has been placed, it has been replaced in the wikitext by the time of saving that revision; there is no variable for the time of saving the particular revision.
 * In particular, templates and images will vary if they are referred to with an expression containing a variable depending on time
 * The current versions of templates and images are used (see also 851); it is not possible to specify a particular revision, unless old versions are given different names, so that, for the system, they are current versions; note that also templates used within these templates may have been revised.

For a true permalink, upload the rendered page as HTML file (if enabled by the system) and link to the URL, e.g. http://upload.wikimedia.org/wikipedia/en/d/d1/Wikitest.html (see also the image page ; by the way, this page was not uploaded because of templates or images, but because of added functionality using Javascript, not allowed in wikitext).

The HTML contains the contents of the templates, so the page is not affected by a change or deletion of a template. It further contains URL-references to images; it is not affected by an image revision, but it is by a deletion.

To produce a wikitext version not depending on templates use "subst:", if necessary recursively.

See also Help:Downloading pages.

Special:Export
Special:Export produces an XML-file, without the MediaWiki user interface, with the wikitext of the current and optionally all old versions of one or more specified pages, with date, time, user name, and edit summary. How it is displayed, e.g. with or without XML tags, and with or without applying newlines, depends on the browser. Some browsers show "+" and "-" links to view or hide selected parts. Alternatively the XML-source can be viewed using the "view source" feature of the browser, or after saving the XML file locally, with a program of choice.

The feature also allows searching for a text in all versions of one or more specified pages. See also XML export.

Image history
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 versions are kept. The image history listing forms part of the image description page, which appears when clicking on the image. The image history consists of this and the old versions themselves.

The image description page consists of three parts:
 * description of the image
 * "Image history" - similar to a page history, with for each version an upload summary and also the file size.
 * "Image links"

The description part has also an edit history; it is labelled, somewhat confusingly, Image:xxx Revision history. It should not be confused with the Image history.

Not kept are images which have been deleted (not to be confused with images that are no longer used in articles), the only record available is the upload log, deletion log and possibly the "votes for deletion" archive. Neither the latest nor older versions are kept by the system, hence it is not possible to undelete an image.

Archiving
Archiving texts in separate pages is superior to using the page history as archive: texts in archive pages can be found searching with Google and using the search feature of Wikipedia. Page histories can only be searched after applying Special:Export. Also, archive pages can be organized and titled afterwards in a suitable way, while e.g. edit summaries can not be supplied afterwards. However, an index of old versions of a page, with links to them, could be prepared.