go get github.com/MarcGrol/parsegit
Use git2json tool (see https://github.com/tarmstrong/git2json)
$ cd <your git project>
$ git2json | python -m json.tool > git_history.json
Analyse committers
$ parsegit -filename=git_history.json -analyze-committers | sort -n -t';' -r -k2
$ parsegit -filename=git_history.json -analyze-files | sort -n -t';' -r -k2