process.rb

#!/usr/bin/env ruby

def to_time(h, m)
  day, month, year = Time.now.to_a[3..5]
  Time.mktime(year, month, day, h.to_i > 23 ? 0 : h, m).to_i
end

summ = 0

Dir['*.txt'].each do |file_name|
  new_lines = File.open(file_name) do |file|
    file.lines.map do |line|
      if line =~ /^\s*(?:\d+\.\d+[, ]+)(\d\d?)[:.](\d\d?)\s*-\s*(\d\d?)[:.](\d\d?)\s+(.+)$/
        diff = to_time($3, $4) - to_time($1, $2)
        diff += 24*60*60 if diff < 0
        diff /= 60*60.0
        summ += diff
        "%2.2f, %d:%d - %d:%d %s" % [diff, $1, $2, $3, $4, $5]
      else 
        line
      end
    end
  end
  File.open(file_name, 'w').write new_lines.join("\n")

end

puts "%2.2f часов отработано" % [summ]