List recent startup and shutdown time from windows event log

worktime.bat

@ruby -x "%~f0" %* & exit /b
#!ruby
# list recent startup and shutdown time
require 'tempfile'
require 'csv'
require 'date'
file = Tempfile.new('event')

CMD = "Get-EventLog System -After (Get-Date).AddMonths(-2) | Where-Object { $_.InstanceId -eq 12 -or $_.InstanceId -eq 13 } | Sort-Object TimeGenerated | Export-CSV #{file.path} -notype "

begin
  file.close
  system("powershell.exe \"#{CMD}\"")
  events = CSV.table(file.path)

  dates = {}
  events.each do |l|
    d = DateTime.parse(l[:timegenerated])
    dates[d.to_date] ||= { start: d.next.to_date.to_datetime, end: d.to_date.to_datetime }

    case l[:instanceid]
    when 12
      dates[d.to_date][:start] = d if d < dates[d.to_date][:start]
    when 13
      dates[d.to_date][:end] = d if dates[d.to_date][:end] < d
    end
  end

  dates.each do |key, d|
    puts "#{key} #{d[:start].strftime('%H:%M')} - #{d[:end].strftime('%H:%M')}"
  end
ensure
  file.close
  file.unlink
end