RubyMine allows you to examine the differences between two revisions of a file or a folder, or between their current local copy and the repository version. The differences are displayed in the Differences viewer. For details on how to filter, navigate and apply changes in the Differences Viewer, see Compare files, folders, and text sources.
Compare a modified file with its repository version
Open the Commit tool window Alt+0.
Select a file and click on the toolbar, or press Ctrl+D.
Compare the current revision of a file or folder with a revision in the same branch
Select a file or a folder in the Project tool window, and choose <your_VCS> | Compare With from the context menu.
Choose a revision you want to compare the current file or folder version with from the dialog that opens.
Compare the current revision of a file or folder with another branch
Select a file or a folder in the Project tool window, and choose <your_VCS> | Compare With Branch from the context menu.
Choose the branch you want to compare the current file or folder version with from the dialog that opens.
on the toolbar, or press Ctrl+D.