Distribution of hours spent typing commands at my zsh shell each day

chart-pie-from-zsh_history.rb

#!/usr/bin/env ruby
# coding: UTF-8

require 'pathname'
require 'googlecharts'
file = Pathname.new 'zsh_history'

dates = {}
file.each_line do |line|
  next unless line =~ /^: /
  seconds = line[/\d+/].to_i
  time = Time.at seconds
  key = time
  key -= 8 * 60 * 60 if time.hour < 8
  key = key.strftime "%F"
  dates[key] = [time] unless dates[key]
  dates[key][1] = time
end

counted = Hash.new(0)
dates.each do |time, pair|
  from, to = *pair
  hours = (to - from) / 3600
  hours = hours.round(0)
  counted[hours] += 1
  puts "#{time} (#{from}-#{to}): #{hours}"
end

puts Gchart.pie(:data => counted.values, :title => 'zsh hours', :size => '400x200', :labels => counted.keys)