git grep has a -h option to omit the filename, but that option has no
effect when given with -c:

~/src/linux$ git grep -h 'example' | head -n 2
  For example, if you distribute copies of such a program, whether
may not distribute the Program at all.  For example, if a patent
~/src/linux$ git grep -hc 'example' | head -n 2
COPYING:2
Documentation/.gitignore:1

By contrast, standard grep does respect -h with -c:

~/src/linux$ grep -rh example * | head -n 2
  For example, if you distribute copies of such a program, whether
may not distribute the Program at all.  For example, if a patent
~/src/linux$ grep -rhc example * | head -n 2
0
2

(Also interesting that git grep omits files with a count of 0, while
grep does not.)

- Josh Triplett