Get names of all files from a folder with Ruby

this code returns only filenames with their extension (without a global path)

Dir.children("/path/to/search/")

=> [file_1.rb, file_2.html, file_3.js]

You may also want to use Rake::FileList (provided you have rake dependency):

FileList.new('lib/*') do |file|
  p file
end

According to the API:

FileLists are lazy. When given a list of glob patterns for possible files to be included in the file list, instead of searching the file structures to find the files, a FileList holds the pattern for latter use.

https://docs.ruby-lang.org/en/2.1.0/Rake/FileList.html

One simple way could be:

dir = './' # desired directory
files = Dir.glob(File.join(dir, '**', '*')).select{|file| File.file?(file)}

files.each do |f|
    puts f
end

In addition to the suggestions in this thread, I wanted to mention that if you need to return dot files as well (.gitignore, etc), with Dir.glob you would need to include a flag as so: Dir.glob("/path/to/dir/*", File::FNM_DOTMATCH) By default, Dir.entries includes dot files, as well as current a parent directories.

For anyone interested, I was curious how the answers here compared to each other in execution time, here was the results against deeply nested hierarchy. The first three results are non-recursive:

       user     system      total        real
Dir[*]: (34900 files stepped over 100 iterations)
  0.110729   0.139060   0.249789 (  0.249961)
Dir.glob(*): (34900 files stepped over 100 iterations)
  0.112104   0.142498   0.254602 (  0.254902)
Dir.entries(): (35600 files stepped over 100 iterations)
  0.142441   0.149306   0.291747 (  0.291998)
Dir[**/*]: (2211600 files stepped over 100 iterations)
  9.399860  15.802976  25.202836 ( 25.250166)
Dir.glob(**/*): (2211600 files stepped over 100 iterations)
  9.335318  15.657782  24.993100 ( 25.006243)
Dir.entries() recursive walk: (2705500 files stepped over 100 iterations)
 14.653018  18.602017  33.255035 ( 33.268056)
Dir.glob(**/*, File::FNM_DOTMATCH): (2705500 files stepped over 100 iterations)
 12.178823  19.577409  31.756232 ( 31.767093)

These were generated with the following benchmarking script:

require 'benchmark'
base_dir = "/path/to/dir/"
n = 100
Benchmark.bm do |x|
  x.report("Dir[*]:") do
    i = 0
    n.times do
      i = i + Dir["#{base_dir}*"].select {|f| !File.directory? f}.length
    end
    puts " (#{i} files stepped over #{n} iterations)"
  end
  x.report("Dir.glob(*):") do
    i = 0
    n.times do
      i = i + Dir.glob("#{base_dir}/*").select {|f| !File.directory? f}.length
    end
    puts " (#{i} files stepped over #{n} iterations)"
  end
  x.report("Dir.entries():") do
    i = 0
    n.times do
      i = i + Dir.entries(base_dir).select {|f| !File.directory? File.join(base_dir, f)}.length
    end
    puts " (#{i} files stepped over #{n} iterations)"
  end
  x.report("Dir[**/*]:") do
    i = 0
    n.times do
      i = i + Dir["#{base_dir}**/*"].select {|f| !File.directory? f}.length
    end
    puts " (#{i} files stepped over #{n} iterations)"
  end
  x.report("Dir.glob(**/*):") do
    i = 0
    n.times do
      i = i + Dir.glob("#{base_dir}**/*").select {|f| !File.directory? f}.length
    end
    puts " (#{i} files stepped over #{n} iterations)"
  end
  x.report("Dir.entries() recursive walk:") do
    i = 0
    n.times do
      def walk_dir(dir, result)
        Dir.entries(dir).each do |file|
          next if file == ".." || file == "."

          path = File.join(dir, file)
          if Dir.exist?(path)
            walk_dir(path, result)
          else
            result << file
          end
        end
      end
      result = Array.new
      walk_dir(base_dir, result)
      i = i + result.length
    end
    puts " (#{i} files stepped over #{n} iterations)"
  end
  x.report("Dir.glob(**/*, File::FNM_DOTMATCH):") do
    i = 0
    n.times do
      i = i + Dir.glob("#{base_dir}**/*", File::FNM_DOTMATCH).select {|f| !File.directory? f}.length
    end
    puts " (#{i} files stepped over #{n} iterations)"
  end
end

The differences in file counts are due to Dir.entries including hidden files by default. Dir.entries ended up taking a bit longer in this case due to needing to rebuild the absolute path of the file to determine if a file was a directory, but even without that it was still taking consistently longer than the other options in the recursive case. This was all using ruby 2.5.1 on OSX.

When loading all names of files in the operating directory you can use

Dir.glob("*)

This will return all files within the context that the application is running in (Note for Rails this is the top level directory of the application)

You can do additional matching and recursive searching found here https://ruby-doc.org/core-2.7.1/Dir.html#method-c-glob

In an IRB context, you can use the following to get the files in the current directory:

file_names = `ls`.split("\n")

You can make this work on other directories too:

file_names = `ls ~/Documents`.split("\n")

if you create directories with spaces:

mkdir "a b"
touch "a b/c"

You don't need to escape the directory names, it will do it automatically:

p Dir["a b/*"] # => ["a b/c"]