Using wildcards in Dir.chdir - ruby?

Question

I have a directory structure, for example like this:

+SOURCE_CODE
          + MODULE_A
            -myfile.txt
          + MODULE_B
            -myfile.txt
          + MODULE_C   
            -myfile.txt

Now I would like to do "Dir.chdir" into each of these directories (MODULE_A, MODULE_B) and than open the "myfile.txt" where I than operate with the strings within these files. It should be something like this:

  Dir.chdir "../SOURCE_CODE/MODULE_*/"
  File.open("myfile.txt") do |f|
    f.each_line do |line|
      ......

I know, it is not possible to use wildcards with "Dir.chdir". But is there an alternative way?

Answer 1

You can use wildcards with Dir.glob:

Dir.glob("../SOURCE_CODE/MODULE_*/myfile.txt") do |filename|
  File.open(filename) do |f|
    f.each_line do |line|
      # ...
    end
  end
end

You can do anything you want inside the block:

Dir.glob("../SOURCE_CODE/MODULE_*/") do |dirname|
  Dir.chdir(dirname)

  File.open("myfile.txt") do |f|
    f.each_line do |line|
      # ...
    end
  end
end

You may need to supply an absolute path to Dir.glob for Dir.chdir to work as expected; I'm not sure. File.expand_path is handy for this.