sleepUntil.rb

#!/usr/bin/env ruby
$KCODE='utf8'
require 'time'
require 'logger'

def usage(error=nil)
	STDERR.print <<-EOS
    sleep until the wakeup time.
  [usage] sleep wakeuptime
  -d
  -v 
  EOS
	STDERR.print "error:#{error}\n" if (error)
end

$log = Logger.new(STDERR)
$log.level = Logger::WARN

def debug(msg)
  $log.debug(msg)
end
def info(msg)
  $log.info(msg)
end
def error(msg)
  $log.error(msg)
  exit
end

if (!ARGV[0])
  usage()
  exit
end
if (ARGV.index('-d'))
  $log.level = Logger::DEBUG
end
now = Time.now
wakeup = Time.parse(ARGV[0])
wakeup = wakeup+(60*60*24) if (wakeup<now)
if (wakeup<now)
  error("suspicious wakeup time:#{ARGV[0]}")
end
sleeptime = wakeup-now
debug("now:#{now.to_s}")
debug("wakeup at:#{wakeup.to_s}")
debug("sleep:#{sleeptime}")
sleep(sleeptime)