$ gem install git_stats

# apt-get install ruby ruby-nokogiri ruby-nokogiri-diff ruby-nokogumbo
# gem install git_stats

$ sudo apt-get install ruby ruby-dev gcc zlib1g-dev make
$ sudo 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, [--out-path=OUT_PATH]                  # Output path where statistics should be written.
                                            # Default: ./git_stats
  l, [--language=LANGUAGE]                  # Language of written statistics.
                                            # Default: en
  f, [--first-commit-sha=FIRST_COMMIT_SHA]  # Commit from where statistics should start.
  t, [--last-commit-sha=LAST_COMMIT_SHA]    # Commit where statistics should stop.
                                            # Default: HEAD
  s, [--silent], [--no-silent]              # Silent mode. Don't output anything.
  d, [--tree=TREE]                          # Tree where statistics should be generated.
                                            # Default: .
  c, [--comment-string=COMMENT_STRING]      # The string which is used for comments.
                                            # Default: //

Generates the statistics of a repository

$ 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
=> [...]