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+.. _dot2-dot3:
+
+========================================
+ Two and three dots in difference specs
+========================================
+
+Thanks to Yarik Halchenko for this explanation.
+
+Imagine a series of commits A, B, C, D...  Imagine that there are two
+branches, *topic* and *master*.  You branched *topic* off *master* when
+*master* was at commit 'E'.  The graph of the commits looks like this::
+
+
+        A---B---C topic
+        /
+   D---E---F---G master
+
+Then::
+
+   git diff master..topic
+
+will output the difference from G to C (i.e. with effects of F and G),
+while::
+
+   git diff master...topic
+
+would output just differences in the topic branch (i.e. only A, B, and
+C).