title: emacs set real time checks on the file
body: <h1>Circumstance</h1>
  <p>As I am testing some programs on the command line and the output is very long, I try to store the output in a file and renew it from time to time. However, the emacs is not checking for renewment. So I need to reopen the file repeatedly.</p>
  <h1>Quesion</h1>
  <h2>emacs</h2>
  <p>I wander if there are good modes or settings for doing that.</p>
  <h2>Others</h2>
  <p>If not, I wander whether there are good text viewing tools to use to solve my problem.</p>
  <p>Thanks a lot ;P</p>