# File lib/bundler.rb, line 292
    def which(executable)
      if File.file?(executable) && File.executable?(executable)
        executable
      elsif ENV['PATH']
        path = ENV['PATH'].split(File::PATH_SEPARATOR).find do |p|
          File.executable?(File.join(p, executable))
        end
        path && File.expand_path(executable, path)
      end
    end