Estimate change of numbers of lines containing keywords

git-log-grep.plot

set xdata time
set timefmt "%Y-%m-%dT%H:%M:%S"

set format x "%b\n%Y"
set ylabel "Total lines"
set yrange [0:12]
plot "固定.tsv" using 1:3 with steps title "固定" lw 2,\
     "ピン.tsv" using 1:3 with steps title "ピン" lw 2

git-log-grep.rb

# usage:
# git log -p app/javascript/mastodon/locales/ja.json config/locales/ja.yml |\
# ruby git-log-grep.rb 固定 ピン
#
require "time"

keywords = ARGV

changes = Hash.new{|h, word| h[word] = Hash.new{|h, time| h[time] = 0}}
ts = nil
$stdin.each_line do |line|
  if x = line.scan(/^Date:\s*(.*)/).flatten.first
    ts = Time.parse(x).utc
  else
    keywords.each do |k|
      if x = line.scan(/^([+-]).*#{k}/).flatten.first
        case x
        when "+"
          changes[k][ts] += 1
        when "-"
          changes[k][ts] -= 1
        end
      end
    end
  end
end

keywords.each do |k|
  File.open("#{k}.tsv", "w") do |f|
    ts = changes[k].keys.sort
    c = 0

    f.puts "#time\tchange\ttotal #{k}"
    ts.each do |t|
      d = changes[k][t]
      c += d
      f.puts [t.iso8601, d, c].join("\t")
    end
  end
end