Case Insensitive Dir.glob In Ruby: Really? It Has To Be That Cryptic?

I’m writing a small file importer in Ruby 1.9, to grab files form an FTP drop. The files are HL7 format, and will have a .HL7 extension. However, I had no guarantee that it would be capitalized .HL7 for the name.

The first version of the code I wrote, to get around this, was ugly:

def import(folder)
  files = []
  files << Dir.glob(folder + "**/*.HL7")
  files << Dir.glob(folder + "**/*.hl7")
  files << Dir.glob(folder + "**/*.Hl7")
  files << Dir.glob(folder + "**/*.hL7")

  files.flatten.each { |file|


After some googling, I found this post where someone is asking for the same thing, wondering if there is a way to do case insensitive Dir.globs. About halfway down the list of replies, I found what I was looking for.

Now my code is much less ugly, and much less intuitive:

def import(folder)
  files = Dir.glob(folder + "**/*.hl7", File::FNM_CASEFOLD)
  files.each { |file|


Really?! File::FNM_CASEFOLD?! Yeah… so much for Ruby’s “intuitive” and “natural language” syntax. At least it works. Now I just have to add a comment to my code to let people know what this is doing.

Any know of a better, more intuitive way of doing case insensitive Dir.globs?

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About Derick Bailey

Derick Bailey is an entrepreneur, problem solver (and creator? :P ), software developer, screecaster, writer, blogger, speaker and technology leader in central Texas (north of Austin). He runs - the amazingly awesome podcast audio hosting service that everyone should be using, and where he throws down the JavaScript gauntlets to get you up to speed. He has been a professional software developer since the late 90's, and has been writing code since the late 80's. Find me on twitter: @derickbailey, @mutedsolutions, @backbonejsclass Find me on the web: SignalLeaf, WatchMeCode, Kendo UI blog, MarionetteJS, My Github profile, On Google+.
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  • Darrell Mozingo

    I’ve done very little Ruby, but couldn’t you at least extract File::FNM_CASEFOLD to a variable named case_insensitive_search or something? I usually prefer variable/method extractions with good names rather than comments.

    • Derick Bailey

      yeah, that’s what i ended up doing- used a method name as the code comments by creating a method called case_insensitive_glob

      • Mister

        Hi. I would do this:

        irb(main):052:0> Dir.entries(“.”)
        => [".", "..", "test3.tXt", "test2.TXT", "test4.text", "test1.txt"]
        irb(main):053:0> txt = Dir.glob(“*”).grep(/txt$/i)
        => ["test3.tXt", "test2.TXT", "test1.txt"]

  • M@

    I know this is quite late, but you could do this:

    Dir["#{ folder }**/*.{hl,Hl,HL,hL}7""].each |file|
    LabResort.import file

    Sort of a middle ground, legibility-wise.