Diff Command

Displays the differences found between two revisions.

svn diff --revision rev1:rev2 PATH
Type Value Description
rev1:rev2 Specifies the revisions to be compared.  
PATH   Location on the file system of the resource to be compared.

If you use the Compare with latest from HEAD (Ctrl (Meta on Mac OS) + Alt + H) from the Working copy view you will be comparing the local file with the HEAD revision file. If you use Compare with BASE revision the local file will be compared with the pristine copy. You can choose to compare the local file with an older revision or two revisions of the same file from the History view.