stat.rb

require 'systemu'
require 'active_support/all'


since = DateTime.new(2019, 6, 1)

while since < Time.now

  from = since.strftime('%Y-%m-%d')
  to = (since + 1.week - 1.day).strftime('%Y-%m-%d')

  git_command = 'git log --all --since="%s" --until="%s"  --pretty=format:"%%h,%%an,%%ar,%%s" | wc -l'%[
    from,
    to,
  ]

  status, stdout, stderr = systemu(git_command)

  puts [from, stdout].join("\t")
  since = since + 1.week
end

command example

ruby stat.rb |termgraph --color red