recursive file list in Ruby

Question

I'm new to Ruby (being a Java dev) and trying to implement a method (oh, sorry, a function) that would retrieve and yield all files in the subdirectories recursively.

I've implemented it as:

def file_list_recurse(dir)
  Dir.foreach(dir) do |f|
    next if f == '.' or f == '..'
    f = dir + '/' + f
    if File.directory? f
      file_list_recurse(File.absolute_path f) { |x| yield x }
    else
      file = File.new(f)
      yield file
    end
  end
end

My questions are:

1. Does File.new really OPEN a file? In Java new File("xxx") doesn't... If I need to yield some structure that I could query file info (ctime, size etc) from what would it be in Ruby?
2. { |x| yield x } looks a little strange to me, is this OK to do yields from recursive functions like that, or is there some way to avoid it?
3. Is there any way to avoid checking for '.' and '..' on each iteration?
4. Is there a better way to implement this?

Thanks

PS: the sample usage of my method is something like this:

curr_file = nil

file_list_recurse('.') do |file|
  curr_file = file if curr_file == nil or curr_file.ctime > file.ctime
end

puts curr_file.to_path + ' ' + curr_file.ctime.to_s

(that would get you the oldest file from the tree)

==========

So, thanks to @buruzaemon I found out the great Dir.glob function which saved me a couple of lines of code. Also, thanks to @Casper I found out the File.stat method, which made my function run two times faster than with File.new

In the end my code is looking something like this:

i=0
curr_file = nil

Dir.glob('**/*', File::FNM_DOTMATCH) do |f|
  file = File.stat(f)
  next unless file.file?
  i += 1
  curr_file = [f, file] if curr_file == nil or curr_file[1].ctime > file.ctime
end

puts curr_file[0] + ' ' + curr_file[1].ctime.to_s
puts "total files #{i}"

=====

By default Dir.glob ignores file names starting with a dot (considered to be 'hidden' in *nix), so it's very important to add the second argument File::FNM_DOTMATCH

Answer 1

How about this?

puts Dir['**/*.*']

Answer 2

According to the docs File.new does open the file. You might want to use File.stat instead, which gathers file-related stats into a queryable object. But note that the stats are gathered at point of creation. Not when you call the query methods like ctime.

Example:

Dir['**/*'].select { |f| File.file?(f) }.map { |f| File.stat(f) }

Answer 3

this thing tells me to consider accepting an answer, I hope it wouldn't mind me answering it myself:

i=0
curr_file = nil

Dir.glob('**/*', File::FNM_DOTMATCH) do |f|
  file = File.stat(f)
  next unless file.file?
  i += 1
  curr_file = [f, file] if curr_file == nil or curr_file[1].ctime > file.ctime
end

puts curr_file[0] + ' ' + curr_file[1].ctime.to_s
puts "total files #{i}"