Reverting

# Overview
A revert is to undo all changes made to an article page after a specific time in the past.  The result will be that the page becomes identical in content to the page saved at that time. However, in the context of the English Wikipedia three revert rule, a revert is defined far more broadly as any change to an article that partially or completely goes back to any older version of an article.
A partial revert is accomplished either by an ordinary edit of the current version, or by editing an old version. The former is convenient, for example, for a partial reversion of a recent addition, while the latter is convenient for a partial reversion of a deletion.
Below is some Wikipedia-oriented text on reversion.

# When to revert

## Do
- Reverting is a decision which should be taken seriously.
- Reverting is used primarily for fighting vandalism, or anything very similar to the effects of vandalism.
- If you are not sure whether a revert is appropriate, discuss it first rather than immediately reverting or deleting it.
- If you feel the edit is unsatisfactory, improve it rather than simply reverting or deleting it.

## Do not
- Do not simply revert changes that are made as part of a dispute. Be respectful to other editors, their contributions and their points of view.
- Do not revert good faith edits. In other words, try to consider the editor "on the other end." If what one is attempting is a positive contribution to Wikipedia, a revert of those contributions is inappropriate unless, and only unless, you as an editor possess firm, substantive, and objective proof to the contrary. Mere disagreement is not such proof. See also Wikipedia:Assume_good_faith.
- Generally there are misconceptions that problematic sections of an article or recent changes are the reasons for reverting or deletion. If they contain valid information, these texts should simply be edited and improved accordingly. Reverting is not a decision which should be taken lightly.
- There's sometimes trouble determining whether some claim is true or useful, particularly when there are few people "on board" who are knowledgeable about the topic. In such a case, it's a good idea to raise objections on a talk page; if one has some reason to believe that the author of what appears to be biased material will not be induced to change it, editors have sometimes taken the step of transferring the text in question to the talk page itself, thus not deleting it entirely. This action should be taken more or less as a last resort, never as a way of punishing people who have written something biased. See also Wikipedia:Neutral point of view/FAQ
- Do not revert changes simply because someone makes an edit you consider problematic, biased, or inaccurate. Improve the edit, rather than reverting it.

# How to revert

## Manual method
- Go to the page, click on "history" at the top ("Page history" in some skins), and click on the time and date of the earlier version to which you wish to revert.
- Then when that page comes up, you'll see something like "(Revision as of 22:19 Aug 15, 2002)" below the title and beneath "From Wikipedia, the free encyclopedia."
- Verify that you've selected the correct version, and click to edit the page, as you would normally.  Important: in the case of vandalism, take the time to make sure that you are reverting to the last version without the vandalism; there may be multiple consecutive vandal edits.
- You'll get a warning, above the edit box, about editing an out-of-date revision.
- After heeding the warning, save the page. Be sure to add the word "revert" and a brief explanation for the revert to the edit summary. Some Wikipedians abbreviate "revert" as "rv" and "rvv" when reverting vandalism. A useful addition is to Wikilink the usernames associated with the versions you are reverting from and to.  For example, a good edit summary would be  rv edits by 219.148.86.36 to last version by David Shear or  rvv edits by 219.148.86.36 to last version by David Shear
The clickable links are created by entering ] (replacing Username with the real IP address or Username for logged-in users, and replacing Username with their real username). Thus for an edit summary that reverts vandalism you would typed exactly:
- Click on "history" again.  A new line will have been added, and you will be able to verify (by clicking on "last") that you undid the vandalism plus all subsequent bona fide edits, if any.  You are responsible for re-doing all the subsequent edits constructive which you undid.
- In a vandalism case where sections of text were simply deleted and then subsequent edits were made by others, it may be easier for you to cut and paste those missing sections of text back in than to revert and then re-do the edits.
- Check the contribution history of the user who vandalized the article. (Click on the IP address for anonymous users or the "contribs" for registered users. If this user is vandalizing many articles, please report them to Wikipedia:Administrator intervention against vandalism.

## User Scripts
- Sam Hocevar's godmode-light.js script adds functionality similar to the admin rollback links described below.  More info at WP:US.
- The vandal edit can also be reverted using popups.

## Reverts do not cause edit conflicts
Reverts never cause an edit conflict - if between the moment you begin the revert process, and the moment you click Post (or Save page), someone else edits and saves the page, their edits will be silently overwritten by the reverted version (but still appear in the page history). So beware of reverting high-traffic pages! Conversely, if it looks like someone has deleted your edits, consider whether it may be one of these unfortunate revision conflicts.

# Undo
- WP:UNDO
Instead of removing all changes after a certain version, the latest versions of MediaWiki allow a single edit to be undone. To do this, view the diff for the edit, and click on 'undo' above the newer version. The software will attempt to create an edit page with a version of the article in which the undone edit doesn't exist but all later edits are retained. The automatic edit summary added when using the undo feature can be found at MediaWiki:Undo-summary.
This feature removes the need to manually redo useful changes since the "undone" edit. However, it will fail if undoing the edit would conflict with later edits. For example, if edit 1000 adds a paragraph and edit 1005 modifies that paragraph, it will be impossible to automatically undo edit 1000. In this case, you must determine how to resolve the problem manually.

# Admin features

## Rollback
On the user contributions page, admins have  the additional "rollback" links at lines which are the last edit made by anybody to that article. Some user scripts (mentioned below) also give users the ability to rollback with an automated edit summary. The rollback link is also shown on the diff page when viewing the difference between any version of the page and the most recent one. 
Clicking on the link reverts to the previous edit not authored by the last editor, with an automatic edit summary of "Reverted edits by X (talk) to last version by Y," which marks the edit as "minor." If, between loading the User Contributions page and pressing "rollback," someone else edits or rolls back the page, or if there was no previous editor, you will get an error message.
The rollback link on the diff page is somewhat misleading because reversion is not necessarily to the old version shown (the diff page may show the combined result of edits including some by other editors, or only part of the edits the rollback button would revert). To see the changes the rollback button would revert, view the corresponding diff page.
Rollbacks should be used with caution and restraint, in part because they leave no explanation for the revert in the edit summary. Reverting a good-faith edit may therefore send the message that "I think your edit was no better than vandalism and doesn't deserve even the courtesy of an explanation." It is a slap in the face to a good-faith editor. If you use the rollback feature for anything other than vandalism or for reverting yourself, it's polite to leave an explanation on the article talk page, or on the talk page of the user whose edit(s) you reverted.

## Bot rollback
In cases of flood vandalism, admins may choose to hide vandalism from recent changes. To do this, add &bot=1 to the end of the url used to access a user's contributions. For example, :Contributions&target=SomePersistentVandal&bot=1.
When the rollback links on the contributions list are clicked, the revert, and the original edit that you are reverting will both be hidden from recent changes unless you click the "bots" link to set hidebots=0. The edits are not hidden from contributions lists, page histories or watchlists. The edits remain in the database and are not removed, but they no longer flood Recentchanges. The aim of this feature is to reduce the annoyance factor of a flood vandal with relatively little effort. This should not be used for reverting a change you just don't like, but is meant only for massive floods of simple vandalism.

# Revert wars considered harmful

## Reasons
Revert wars are usually considered harmful for the following reasons:
- They disrespect the work of the contributor. Being reverted can feel a bit like a slap in the face: "I worked hard on those edits, and someone just rolled it all back"
- They cause ill-will between users and negatively destabilize articles
- They make the page history less useful, waste space in the database
- They make it hard for other people to contribute, and flood recent changes and watchlists

## Three revert rule
In consideration of the harm of reverting, Wikipedia policy states that you may not revert any article more than three times in the same day. This is a very strict limit, not a given right; you should not revert any one article more than three times daily.

## Explain reverts
When a revert is necessary, it is very important to let people know why you reverted. This helps the reverted person because they can remake their edit, but fixing whatever problem it is that you've identified.
Explaining reverts also helps other people. For example, it lets people know whether they need to even view the reverted version (in the case of, eg, "rv page blanking"). Because of the lack of non-verbal communication online, if you don't explain things clearly people will probably assume all kinds of nasty things, and that's one of the possible causes for edit wars.
If your reasons for reverting are too complex to explain in the edit summary, drop a note on the Talk page. A nice thing to do is to drop the note on the Talk page first, and then revert, rather than the other way round. Sometimes the other person will agree with you and revert for you before you have a chance. Conversely, if someone reverts your change without apparent explanation, you may wish to wait a few minutes to see if they explain their actions on the article's talk page or your user talk page.

## Exceptions
Edits that don't contribute to edit warring are generally considered to be exceptions to the 3-revert rule.  Such edits may include reverts of obvious vandalism, reverts of banned users, or removal of potentially libelous text.  See Wikipedia:Three-revert rule#Exceptions for a fuller explanation.
Please request protection rather than reverting. Violation of this rule may lead to protection of the page on the version preferred by the non-violating party; blocking; or investigation by the Arbitration Committee.