title: vim: How to search/replace in all opened files?
body: <p>If I use :vimgrep, it searches all files under current directory. But my requirement is to search/replace among all opened files.</p>
  <p>E.g. I'm using vim to open 3 files at the same time</p>
  <pre><code>vim 1.cpp 2.cpp 3.cpp
  </code></pre>
  <p>I wish to:</p>
  <blockquote>
  <ol>
  <li><p>search all functions called &quot;main&quot; and display in quickfix window, among all 3 files.</p>
  </li>
  <li><p>Replace all &quot;hello&quot; with &quot;world&quot; in all 3 files.</p>
  </li>
  </ol>
  </blockquote>