Being able to compare and work with the changes between two different revisions of a page can prove to be very useful when reviewing past modifications, making adjustments based on a previous version, or merging past and current content. Platforms like MediaWiki and WordPress have a feature called ‘diff‘ which shows the differences between two versions of a page, identifying the exact changes by line. While the WMS-Drupal system has an annotation feature which allows edit summaries to be logged by the editor, it is currently unable to highlight changes to the content. This is where external diff software becomes useful.
WinMerge is free and open-source diff software for Windows. The user pastes the content of each version of the text to be compared into the two main panes. A slight inconvenience to using it with WMS is that the editing screen of an old revision cannot be accessed without reverting to that revision. This makes it difficult to retrieve the HTML behind the page. A solution would be to display the older revision and use your browser’s ‘view source’ feature to see the HTML. Select the text within
<div class="content">—this should be the actual main content of the page. Note that some elements, particularly those that are created by placing [ ] tags in the text (as course titles and embedded videos are) will appear as different HTML.
After text has been entered into the two comparison panes and the view is refreshed, the software will identify and highlight all lines with differences. The user can quickly skim through these or individually navigate through each one of them. Any necessary changes can be made directly to one of the versions, or the merge tools can be used to replace one or more lines in one version with the respective line(s) in the other. When all the changes have been made, the text can be copied and pasted back into the WMS HTML editor and saved.
In addition to text comparison, WinMerge has the ability to compare files and folders, which may be useful for syncing between two sources. For more information on WinMerge’s features, check out WinMerge’s about page. If you’re interested in other diff software (for another OS), see Wikipedia’s comparison of file comparison tools.