Illustrate mtime behavior

mtime_test.rb

require 'fileutils'

dir = File.expand_path('../mtime', __FILE__)
file = "#{dir}/file.txt"
format = "%5s:%-20s  %s"

FileUtils.rm_rf(dir)
FileUtils.mkdir_p(dir)

puts format % [:dir, "mkdir", File.mtime(dir)]
sleep(1)

FileUtils.touch(file)
puts format % [:dir, "touch file", File.mtime(dir)]
sleep(1)

File.open(file, 'w') {|io| io << 'content' }
puts format % [:dir, "mod file", File.mtime(dir)]
sleep(1)

FileUtils.rm(file)
puts format % [:dir, "rm file", File.mtime(dir)]
sleep(1)

FileUtils.touch(file)
puts format % [:file, "touch", File.mtime(file)]
sleep(1)

File.open(file, 'w') {|io| io << 'content' }
puts format % [:file, "mod", File.mtime(file)]
sleep(1)

FileUtils.touch(file)
puts format % [:file, "touch", File.mtime(file)]