title: Indent code using vim autocommand
body: <p>I want use the indent linux utility to indent the current file on saving. I tried </p>
  
  <pre><code>autocmd BufWritePre *.[ch] :!indent -kr -nut %
  </code></pre>
  
  <p>in my .vimrc file (~/.vim).</p>
  
  <p>Manually I tried that command </p>
  
  <pre><code>:!indent -kr -nut %
  </code></pre>
  
  <p>it works only after prompting me to load the file, as below,</p>
  
  <pre><code>See ":help W12" for more info.
  [O]K, (L)oad File:
  </code></pre>