Iterate through every file in one directory

Question

How do I write a loop in ruby so that I can execute a block of code on each file?

I\'m new to ruby, and I\'ve concluded that the way to do this is a do each loop.

Answer 1

Dir has also shorter syntax to get an array of all files from directory:

Dir['dir/to/files/*'].each do |fname|
    # do something with fname
end

Answer 2

Dir.new('/my/dir').each do |name|
  ...
end

Answer 3

I like this one, that hasn't been mentioned above.

require 'pathname'

Pathname.new('/my/dir').children.each do |path|
    puts path
end

The benefit is that you get a Pathname object instead of a string, that you can do useful stuff with and traverse further.

Answer 4

To skip . & .., you can use Dir::each_child.

Dir.each_child('/path/to/dir') do |filename|
  puts filename
end

Dir::children returns an array of the filenames.

Answer 5

As others have said, Dir::foreach is a good option here. However, note that Dir::foreach and Dir::entries will always include . and .. (the current and parent directories). You will generally not want to work on them, so you can use Dir::each_child or Dir::children (as suggested by ma11hew28) or do something like this:

Dir.foreach('/path/to/dir') do |filename|
  next if filename == '.' or filename == '..'
  # Do work on the remaining files & directories
end

Dir::foreach and Dir::entries (as well as Dir::each_child and Dir::children) also include hidden files & directories. Often this is what you want, but if it isn't, you need to do something to skip over them.

Alternatively, you might want to look into Dir::glob which provides simple wildcard matching:

Dir.glob('/path/to/dir/*.rb') do |rb_filename|
  # Do work on files & directories ending in .rb
end

Answer 6

This is my favorite method for being easy to read:

Dir.glob("*/*.txt") do |my_text_file|
  puts "working on: #{my_text_file}..."
end

And you can even extend this to work on all files in subdirs:

Dir.glob("**/*.txt") do |my_text_file| # note one extra "*"
  puts "working on: #{my_text_file}..."
end