Tabs to spaces converter for files. Ruby 1.9 or greater.

tabs2spaces.rb

require 'optparse'

module TabsToSpaces
  def self.start(args, options)
    @options = options

    display_options_and_args(args)
    process(args.first)
  end

  def self.process(arg)
    substring = String.new.tap { |s| @options[:amount].to_i.times { s << ' ' } }

    case
    when is_not_file_or_dir?(arg)
      # Do nothing
    when File.directory?(arg)
      p "Processing #{arg} as directory" if verbose?

      Dir.open(arg).each do |dir|
        next if is_not_file_or_dir?(dir)
        next_dir = [arg, dir].join('/').gsub('//', '/')

        # Recursively process directories
        process(next_dir)
      end if @options[:recursive]
    when File.extname(arg) =~ /#{@options[:filetypes]}/
      p "Processing #{arg}" if verbose?

      if File.extname(arg) =~ /#{@options[:exclusions]}/
        p "#{arg} matches the exclusion list. Skipping"
      else
        File .open(arg, 'r+') do |file|
          subbed = file.read.gsub(/\t/, substring)
          file.rewind
          file.write subbed
        end
      end
    else
      p "#{arg} does not qualify to be parsed. Skipping" if verbose?
    end
  end

  private

  def self.is_not_file_or_dir?(arg)
    arg == '.' || arg == '..'
  end

  def self.verbose?
    @options[:verbose]
  end

  def self.display_options_and_args(args)
    p @options if verbose?
    p args if verbose?
  end
end

if __FILE__ == $0
  options = {
    amount:     2,
    filetypes:  ".rb|.erb|.css|.js|.rake",
    exclusions: '.json|.yml|.scssc'
  }

  optparse = OptionParser.new do |opts|
    opts.banner = "Usage: tabs2spaces.rb directory/file [options]"

    opts.on("-v", "--verbose", "Run verbosely") do |v|
      options[:verbose] = v
    end

    opts.on("-r", "--recursive", "Traverse through directories and process") do |r|
      options[:recursive] = r
    end

    opts.on("-a", "--amount [INTEGER]", "Specify the amount of spaces to substitute (default 2)") do |a|
      options[:amount] = a
    end

    opts.on("-f", "--filetypes [EXTENSIONS]", "Specify filetypes to process (Regex format. Default: '.rb|.erb|.css|.js|.rake')") do |f|
      options[:filetypes] = f
    end

    opts.on("-e", "--exclude [EXTENSIONS]", "Specify exclude certain filetypes (Regex format. Default: '.json|.yml|.scssc')") do |e|
      options[:exclusions] = e
    end
  end

  optparse.parse!

  if ARGV.size != 1
    puts optparse.help
    exit
  end

  TabsToSpaces.start(ARGV, options)
end