[ruby] run shell command, read output (from Bundler code)

gistfile1.rb

    def sh(cmd, &block)
      out, code = sh_with_code(cmd, &block)
      code == 0 ? out : raise(out.empty? ? "Running `#{cmd}' failed. Run this command directly for more detailed output." : out)
    end

    def sh_with_code(cmd, &block)
      cmd << " 2>&1"
      outbuf = ''
      Bundler.ui.debug(cmd)
      Dir.chdir(base) {
        outbuf = `#{cmd}`
        if $? == 0
          block.call(outbuf) if block
        end
      }
      [outbuf, $?]
    end