Showing Josh how MRI works.

thread_log_test.txt

~/Desktop [ruby 2.0.0p247]$ cat dont_close_my_logger.rb
require "logger"

log    = ARGV.shift or abort "USAGE:  #{$PROGRAM_NAME} LOG"
logger = Logger.new(log)

threads  = [ ]
threads << Thread.new do
  logger.info "Thread one started.  Sleeping a bit to make sure thread two is going..."
  sleep 1
  logger.info "Exiting thread one."
end
threads << Thread.new do
  logger.info "Thread two started.  Sleeping to make sure thread one stops..."
  sleep 3
  logger.info "Exiting thread two."
end
threads.each(&:join)

~/Desktop [ruby 2.0.0p247]$ ruby -v dont_close_my_logger.rb result.log
ruby 2.0.0p247 (2013-06-27 revision 41674) [x86_64-darwin12.4.0]
~/Desktop [ruby 2.0.0p247]$ cat result.log
# Logfile created on 2013-08-22 14:05:12 -0500 by logger.rb/36483
I, [2013-08-22T14:05:12.533654 #13569]  INFO -- : Thread one started.  Sleeping a bit to make sure thread two is going...
I, [2013-08-22T14:05:12.533786 #13569]  INFO -- : Thread two started.  Sleeping to make sure thread one stops...
I, [2013-08-22T14:05:13.534145 #13569]  INFO -- : Exiting thread one.
I, [2013-08-22T14:05:15.534440 #13569]  INFO -- : Exiting thread two.