$ gem install git_stats

$ git_stats
Commands:
  git_stats generate        # Generates the statistics of a repository
  git_stats help [COMMAND]  # Describe available commands or one specific command

$ git_stats help generate
Usage:
  git_stats generate

Options:
  p, [--path=PATH]          # Path to repository from which statistics should be generated.
                            # Default: .
  o, [--output=OUTPUT]      # Output path where statistics should be written.
                            # Default: ./git_stats
  l, [--language=LANGUAGE]  # Language of written statistics.
                            # Default: en
  f, [--from=FROM]          # Commit from where statistics should start.
  t, [--to=TO]              # Commit where statistics should stop.
                            # Default: HEAD
  s, [--silent]             # Silent mode. Don't output anything.

$ git_stats generate
  git rev-list --pretty=format:'%h|%at|%ai|%aE' HEAD | grep -v commit
  git shortlog -se HEAD
  ...

$ git_stats generate -o stats --langugage de
  git rev-list --pretty=format:'%h|%at|%ai|%aE' HEAD | grep -v commit
  git shortlog -se HEAD
  ...

> repo = GitStats::GitData::Repo.new(path: '.', first_commit_sha: 'abcd1234', last_commit_sha: 'HEAD')
> repo.authors
=> [...]
> repo.commits
=> [...]
> commit.files
=> [...]