Help talk:Diff

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How to get at an uploaded file's date[edit]

I'm working with a company designing its own wiki, and we're facing a sticky point ...

We have many internal company documents, and want to get at a doc's latest update, i.e., when was Image:User dino.jpg last updated? When was the annual report last changed? And that data on interest rates ...

Is there a way to "grab" these data & display them? Or just grab them — we'll figure out how to display them.

I realize, this may seem from left field, but thought I'd toss it out there. Thanks for any ideas. You may reply here or on my talk page.

dino 14:09, 4 September 2007 (UTC)

For an uploaded file, this is in the file history section of the image page. For instance, Image:User dino.jpg was last updated 03:43, February 2, 2004. Superm401 - Talk 10:32, 21 April 2008 (UTC)

The instructions here don't work[edit]

I am attempting to file a complaint of improper behavior by a certain administrator--obviously, I don't want to go into details of that outside the filing itself--and attempted to include a link to the evidence of his behavior. I followed the instructions here to the letter (do not dispute that, as I double and triple checked), but the resulting link goes to Wikipedia's main, introductory ("Welcome") page. Please update these instructions to reflect the system's current requirements as soon as possible, as I have no doubt that a significant delay in filing the complaint will be held against its credibility (or is it possible for this administrator to have put some sort of a block on this?). Thank you. Ted Watson (talk) 20:22, 10 January 2008 (UTC)

I suggest you set out a full example so that we can all see it not working. Thanks, Bovlb (talk) 20:46, 21 March 2008 (UTC)
See Wikipedia:Simplest diff guide.
Try this: Click the "history" tab at the top of the page. Then, in the list of versions, click "last" (the second link from the left) on one of them. You should then be viewing a diff of that version compared to the previous version. See if your browser somehow displays the URL of the page you're then looking at. Copy that URL. Put it between single square brackets. If this doesn't work, tell us which step it stopped working at. For the instructions on this page not working for you: Try it on a page that has nothing to do with your improper behaviour complaint. When it still doesn't work, post the URL here so we can see what you were trying to do. In general, when you'd like help with things, you can usually get a quick response either at the help desk or by putting {{helpme}} on your talk page along with your question. I hope this helps. --Coppertwig (talk) 22:26, 21 March 2008 (UTC)
As my description above makes crystal clear, there was no "step it stopped working at" but the simple fact that the resultant link went to the "Welcome" page rather than the intended diff. It absolutely amazes me how many responses like this I have received from Wiki administrators, responses which show a complete lack of having studied the situation at hand. I can, if you don't like me saying that, provide links to each and every one of them to prove it. Ted Watson (talk) 17:54, 22 March 2008 (UTC)
I have had this problem also. If a link or URL is defective, it usually defaults to the "Welcome" page, and it is easy to make a defective link. What I do to get a DIFF is: Go to revision history. RIGHT-click on "last" for the required DIFF. Left-Click on "Copy shortcut" from the drop-down menu which should appear (I am using IE6). The correct URL is now in my clip-board. ControlV (copy) gets the URL into whatever document I am writing, and it needs one square bracket at each end [diff]. That's how it works for me, does that get it for you too? --Newbyguesses - Talk 19:48, 22 March 2008 (UTC)

Just ran an experiment here and hitting my keyboard's "Ctrl" and letter "v" keys put a link address in this field that certainly seems to be the edit history entry that I right clicked on just before starting this. Tried "Preview" and, yeah, that's it. It look like an external link which is not supposed to be the case, to my understanding, but at least I can do it. After all, I can make the link's true nature clear in the posting. And somebody has as already conceded that the formally posted instructions need to be changed, so I'd agree that this is resolved. I feel that it would be more appropriate for someone on Admin's side to post that tag, rather than me. Thanks. Ted Watson (talk) 18:40, 23 March 2008 (UTC)

Actually, I changed my mind. The instructions are correct. However, I also inserted simple instructions for making ordinary diff links, copied from Wikipedia:Simplest diff guide. See User talk:Coppertwig#Diff problem. Don't worry: diff links do look like external links when other people do them, too. --Coppertwig (talk) 22:19, 23 March 2008 (UTC)
Actually, your instructions don't work for either of the top two edit history entries, each of which already has a black dot in the radio button, which (I assume) causes the drop box to be different, almost nothing in it can be selected. I must find time to experiment with the standard instructions and soon. Ted Watson (talk) 20:57, 24 March 2008 (UTC)


What the heck? nothing seems to work —Preceding unsigned comment added by (talk) 23:43, 11 March 2008 (UTC)

How do I make an internal link to a diff?[edit]

This page does a good job of describing how to make external links, as well as general hyperlinks outside of Wikipedia, to an overview of different versions of a page. But how do you make an internal link relevant to the same? I would appreciate it if somebody posted that information to this help page. Thanks in advance, --Luigifan (talk) 15:08, 10 February 2009 (UTC)

I'm going to bump this 4+ year old thread because my question is: "Why does the Help:Diff#Linking_to_a_diff section not include instructions on using Template:Diff?" Thanks... Technical 13 (talk) 14:10, 8 April 2013 (UTC)
I'll try to add that information to the section. 8ty3hree (talk) 07:33, 6 August 2013 (UTC)
 Done by User:93 (07:37 6/Aug/13). Thanks, -- -- -- 07:05, 28 August 2015 (UTC)

Explanation of Colours Section[edit]

What is written: "Where whole paragraphs have been removed or inserted, the other side is blank (white)." Since I chose a skin that yields a light-green background while I'm logged in, the above statement seems to be correct only part of the time. The "(white)" in the sentence probably should be removed, or perhaps a statement that the colour depends upon the user's skin that was chosen?

By the way, I made a couple of minor spelling edits--I just changed "is" to "are", and "hilighted" to "highlighted". I sincerely hope you don't mind.  .`^) Painediss`cuss (^`.  04:54, 8 March 2009 (UTC)

The Help page made my brain explode: Simplify the Introduction[edit]

The primary example at the top of the page says "This is only shown when viewing the diff between the recent version of a page and the last version by an author other than the one of the most current version." *phew* Well that just totally didn't help me it made my brain hurt. I'm afraid the bold red text only made it harder.

What I wanted to see in the first example was (left,yellow) "This text only appears in the old version of the page" and (right,green) "This text only appears in the newer version of the page (it may be a small adjustment or a complete replacement of the block on the left)". In other words, simplify that top example. (I don't know if my descriptions were really accurate. In my diffing systems I usually expect red=removed(left), yellow=changed(both sides), green=added(right).)

Where to put the text I just requested be removed? Well let's simplify that too. Further down the page, add a note/factoid: Wikimedia's diff system simplifies the diffing process by skipping past (compressing) multiple edits made by the same author.

I appreciate that the exact details of the system should be available. But most users going after Help or Documentation would rather get easy info fast, and come back later and scroll down if they want to know the details. Thanks. (talk) 19:56, 21 August 2009 (UTC)

I certainly agree with that principle. But feel free to edit the page yourself if you think you can improve it.--Kotniski (talk) 08:38, 22 August 2009 (UTC)

Category change[edit]

{{editprotected}} I'm having a bash at categorizing help pages, could you change to Category:Wikipedia page help (or add as an extra cat). Whilst we're here not sure if this page really warrants full protection, certainly semi, but first page of its kind I've encountered for a bit. Lee∴V (talkcontribs) 01:09, 15 February 2010 (UTC)

I've reduced the protection level to semi. You can now make your edit. - Rjd0060 (talk) 12:48, 15 February 2010 (UTC)
Many thanks !Lee∴V (talkcontribs) 14:17, 15 February 2010 (UTC)

The Help page made my brain explode 2[edit]

See above. Yeah, me too. It says "Some of the diffs are dummies", and the page always makes me feel some of the users (=me) are, too. To help the dummies, I've written the Simple diff and link guide: a page that I can understand myself. I have now put it under "See also" in Help:Diff, where the Complete diff and link guide already resided. Please, if you have some fancy options to add to the "guide" series, put them in the Complete, not the Simple (and definitely not the Simplest). Bishonen | talk 13:39, 10 February 2011 (UTC).

Skipping vandalism[edit]

Is there a way to step through the diff pages without having to see every instance of reverted vandalism. I work on a page that is often vandalized by some jerk, then immediately reverted by a hero editor. That process covers perhaps 70 or 80% of the edits. Thus it is hard to step through the history to get a sense of how the content is changing over time, and who is contributing. I'd love to be able to go through a history that ignores any entries that were reverted within an hour or so. Phytism (talk) 16:02, 19 August 2011 (UTC)

Simplified diff URLs[edit]

I've seen Wikipedians use a simplified style of URL for linking to diffs and was surprised that this little nugget was not covered on the help page, so I decided to be bold and simply add it (yeah, those templates are also neat; cool to learn about them). For newbies who are repelled by complicated-looking URLs, perhaps this style would be even better suitable and should be covered in the "simple" and "simplest" guides? What do you think? --Florian Blaschke (talk) 21:15, 25 September 2011 (UTC)

In fact, I believe that mentioning the possibility of using {{oldid2|12345678}} in the simple guides is sensible, as well. How's that not simple? You just need the revision ID for this one, and you can simply copy and paste the template code, look for the ID, and replace the placeholder with it. --Florian Blaschke (talk) 16:03, 2 October 2011 (UTC)

Also, using {{diff2|12345678}} for a diff is just as simple. --Florian Blaschke (talk) 16:10, 2 October 2011 (UTC)

Has there been a recent change in Difference between revisions?[edit]

My Difference between revisions look very different than the did a few weeks ago. Just wondering if something has changed for everyone or maybe I simply changed some preference I did not mean to? Ottawahitech (talk) 04:47, 15 May 2012 (UTC)

Yes. The new default scheme is yellow/blue. You can restore the old yellow/green scheme by ticking a preference box: Gadgets > Appearance > Display diffs with the old yellow/green colors and design. -- John of Reading (talk) 07:15, 15 May 2012 (UTC)
Thank you, John of Reading. I tried to restore the old scheme, but I believe it is more than colors that have changed. It used to be easier to tell what changed from a previous version - sorry I never paid attention to why it worked when it worked. Ottawahitech (talk) 16:04, 22 May 2012 (UTC)

Template simulation[edit]

I've created a template for simulating diffs: {{wiki diff}}. benzband (talk) 19:12, 18 May 2012 (UTC)

Diff wikilinks[edit]

gerrit:63395 was added to MediaWiki 1.23wmf12 which has now been deployed to all Wikimedia wikis. This makes it possible to make diff links with Special:Diff. One of the advantages is that it works in edit summaries. The examples in gerrit:63395:

Will somebody update help pages? PrimeHunter (talk) 23:48, 7 February 2014 (UTC)

Semi-protected edit request on 21 February 2014[edit]

Symbiosis Public School

Dipakdotnet (talk) 06:14, 21 February 2014 (UTC)

Not done: this is the talk page for discussing improvements to the page Help:Diff. Please make your request at the talk page for the article concerned. — {{U|Technical 13}} (tec) 16:12, 21 February 2014 (UTC)

What is the diff algorithm used in Wikipedia, and can we improve it?[edit]

I'm an electrical engineer that does a lot of programming and, of recent, I am unimpressed with the diff utility that Wikipedia uses.


Now the essential difference between these two versions is simply the insertion of this text:

a signal which has no negative-frequency components is called an analytic signal<ref>``Mathematics of the Discrete Fourier Transform (DFT), with Audio Applications --- Second Edition'', by Julius O. Smith III, W3K Publishing, 2007, ISBN 978-0-9745607-4-8. Copyright © 2014-04-21 by Julius O. Smith III Center for Computer Research in Music and Acoustics (CCRMA), Stanford University,[7/16/2014 1:07:57 PM]</ref>. The

But the diff shows that the entire remaining paragraph is deleted (highlighted in orange), then shows the identical text inserted as a new paragraph. So it was very difficult to manually compare that the text that was incorrectly shown as "deleted" and "added" to see that the text is verbatim identical.

This is sooo unnecessary. At the very least the algorithm should do a character-by-character compare from the beginnings of the two file to the first byte that is different (which it does) and it should do the same from the ends of the two files going backwards until it hits a difference (which it does not do). In the case that there are changes at disparate spots in the files, it should look for larges swaths of text that are identical (but positioned differently) and make sure that they are not displayed as "different". That's harder, I know, but at least, when the difference is a contiguous insertion of text, the diff utility should show it as such.

What gives about this? What is the software that is used and is the source code available to be modified? Who then makes or builds it into the build of the project? Any email addresses of pertinent developers?

Thanks. (talk) 18:41, 16 July 2014 (UTC)

Hi. The computer program is called MediaWiki. It is free and open-source. So, yes, you can definitely study and change the algorithm in it – and you may contribute it after that. Wikipedia itself, however, is rather slow and very cautious in adapting the latest versions of MediaWiki. Perhaps User:Whatamidoing (WMF) might be able to tell you more.
Best regards,
Codename Lisa (talk) 20:17, 16 July 2014 (UTC)
I find that particular diff problem to be incredibly annoying, too. It sounds to me that you might want to see part of User:Halfak's presentation today, which starts about half an hour into this recording:
For more general information about contributing as a developer, start at mw: How to become a MediaWiki hacker. You can follow the links to more details. Whatamidoing (WMF) (talk) 23:49, 16 July 2014 (UTC)
I don't know why this is still not fixed. I merely added two line breaks and marked the change as minor in this change, but the diff shows that I deleted a big chunk of paragraph 1, crapped all over paragraph 2 completely changing it into something entirely different, and added new paragraphs 3 and 4. That looks nothing minor! And to anyone checking out this diff, he will be like WTF is Agent007bond doing vandalizing Wikipedia instead of executing top secret missions from the Queen, and having fun with Bond girls... -- ADTC Talk Ctrb 13:33, 3 April 2016 (UTC)
Hi, Agent007bond (with cc to Whatamidoing (WMF)). I believe that WP:wikEdDiff will solve most of your issues with the stock Diff output. You can enable widEdDiff in the Gadgets tab in your Preferences, in the Editing section. Be sure to save your changes.
The old Diff output will show up below the Improved Wide Diff, so you can still see the discrete version of the changes you made. Cheers! {{u|Checkingfax}} {Talk} 20:00, 10 April 2016 (UTC)
Then the question to ask is, why is the "improved" wide diff less improved than the old diff? For the record, I do see the old diff. That is not the point. If someone who has the default settings on Wikipedia looks at the diff (just try loading the diff page in an incognito or private browser window), he or she is only going to see the "improved" but totally incorrect diff. Telling me to change a setting is not useful here because you can't ask everyone to change a setting to fix the problem, and you definitely can't tell Wikipedia to go back to the old diff system. -- ADTC Talk Ctrb 08:38, 16 April 2016 (UTC)
Agent007bond is right, the Wikimedia diff algorithm is absolutely dreadful and it's been terrible for a long time. Quale (talk) 10:02, 23 April 2016 (UTC)

Semi-protected edit request on 15 October 2014 -- article on Sebhat Ephrem[edit]

"Sebhat is a secret Jehovah Witness believer." should be removed -- potentially libelous, could result in prison and torture of this man. He might be related to a Witness or studying the Bible with a Witness or even attend meetings of Jehovah's Witnesses, but such actions do not constitute membership as one of Jehovah's Witnesses (please contact Jehovah's Witnesses headquarters for confirmation). Witnesses do not make a secret of membership, but openly and publicly are baptized and preach to others. (talk) 01:50, 15 October 2014 (UTC)

Red information icon with gradient background.svg Not done: That text only appears on Sebhat Ephrem which is not protected. Stickee (talk) 02:19, 15 October 2014 (UTC)

'How it looks' section - Link for '(thanks) ?'[edit]

Greetings, For the time being, I patched in a (thanks) for the How it looks section, right-column only. That way it matches what the software looks like. Being somewhat new to Wikipedia, I don't know if that can be hotlinked or not; and if it should be done? Regards,  JoeHebda (talk)  15:58, 21 January 2016 (UTC)

I have linked it to Wikipedia:Notifications/Thanks and added an explanation.[1] PrimeHunter (talk) 16:21, 21 January 2016 (UTC)
PrimeHunter – Tournesol.png Thank you for this update. For the Wikipedia:Tip of the day I'm working on three new Help related tips & plan to include your explanation on one of them. Cheers!  JoeHebda (talk)  19:14, 21 January 2016 (UTC)


Accurate diff codes only seem to show up when clicking a diff directly from a history page.

If we come across them through navigation beyond that, it's instead diff=prev or diff=next.

The only number generated is oldid. I know linking ?oldid= directly just links to an old version of a page. Is there a template for that?

I believe the default, if you use an oldid number as a diff, is that the diff is between that and the previous one. For example:

These identify the very same change even though there is different numbers in the oldid field.

Given the confusing aspect of numberless diffs (prev/next) a modification in the special:diff function tailored to accept that alternate input could be cool. Ranze (talk) 06:29, 19 December 2016 (UTC)

I guess by "accurate" you mean that diff= and oldid= are both revision numbers. {{oldid}} links to an oldid. I'm not sure what you mean by default given your examples. is the diff between oldid=68158910 and the previous edit but that is explicitly requested with diff=prev so I wouldn't call it a default there. is the diff between oldid=68158910 and the next edit. is the diff between oldid=68158910 and the current version.
Your example oldid only has one newer version so cur and next is the same.
Special:Diff already accepts prev, next and cur, e.g.: Special:Diff/68158910/prev, Special:Diff/68158910/next, Special:Diff/68158910/cur. PrimeHunter (talk) 11:38, 19 December 2016 (UTC)

Semi-protected edit request on 30 January 2017[edit]

== Heading text == Royalbazid (talk) 14:05, 30 January 2017 (UTC)

Not done: this is the talk page for discussing improvements to the page Help:Diff. Please make your request at the talk page for the article concerned. JTP (talkcontribs) 14:12, 30 January 2017 (UTC)

Go ahead and accept changes Sierragold2016 (talk) 06:13, 5 November 2017 (UTC)

Semi-protected edit request on 24 October 2017[edit]

Huicao (talk) 03:18, 24 October 2017 (UTC)
Not done: Empty request Eggishorn (talk) (contrib) 03:36, 24 October 2017 (UTC)

Semi-protected edit request on 26 October 2017[edit]

Christine Boyd (talk) 02:54, 26 October 2017 (UTC)
Not done: Empty request Eggishorn (talk) (contrib) 04:40, 26 October 2017 (UTC)