How to check if a given directory exists in Ruby

ruby directory
Ash picture Ash · Jul 6, 2009 · Viewed 125.6k times · Source

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.

For some reason, my code isn't working and always returns true even if it's false:

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

What am I doing wrong?

Answer

Emily picture Emily · Jul 6, 2009

If it matters whether the file you're looking for is a directory and not just a file, you could use File.directory? or Dir.exist?. This will return true only if the file exists and is a directory.

As an aside, a more idiomatic way to write the method would be to take advantage of the fact that Ruby automatically returns the result of the last expression inside the method. Thus, you could write it like this:

def directory_exists?(directory)
  File.directory?(directory)
end

Note that using a method is not necessary in the present case.

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