# File lib/bundler.rb, line 393
    def which(executable)
      if File.file?(executable) && File.executable?(executable)
        executable
      elsif paths = ENV["PATH"]
        quote = '"'.freeze
        paths.split(File::PATH_SEPARATOR).find do |path|
          path = path[1..-2] if path.start_with?(quote) && path.end_with?(quote)
          executable_path = File.expand_path(executable, path)
          return executable_path if File.file?(executable_path) && File.executable?(executable_path)
        end
      end
    end