Simple commit hook to update a file. This is mostly for my edification and use, and will probably be of no help to anyone else.

gistfile1.sh

#!/bin/sh
false|tee stats # empty out the stats file
git diff --numstat HEAD HEAD~1 | egrep "txt|rtf|md" >> stats #write the stats file for any text-like files committed.
/Users/username/bin/bookBoard.rb # run a specific ruby script at the end of the commit process