development history for when a code snippet occurred in a change. This makes it
possible to track when a code snippet was added to a file, moved or copied
between files, and eventually deleted or replaced. It works by searching for
-a text string in the diff. A small example:
+a text string in the diff. A small example of the pickaxe interface
+that searches for `blame_usage`:
-----------------------------------------------------------------------------
$ git log --pretty=oneline -S'blame_usage'