如何检查Ruby中是否存在给定目录 - How to check if a given directory exists in Ruby

问题：

I am trying to write a script which automatically checks out or updates a Subversion URL based on whether a specified directory exists or not.我正在尝试编写一个脚本，该脚本根据指定的目录是否存在自动检出或更新 Subversion URL。

For some reason, my code isn't working and always returns true even if it's false:出于某种原因，我的代码不起作用，即使它是假的，也总是返回真：

def directory_exists?(directory)
  return false if Dir[directory] == nil
  true
end

What am I doing wrong?我究竟做错了什么？

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解决方案：

参考一： https://en.stackoom.com/question/4YJW
参考二： https://stackoom.com/question/4YJW