title: vim e518: unknown option:
body: <p>I have a text file on a unix system.  The following text file content creates the problem:</p>
  
  <pre>good: ok line
  vi: bad line
  ok: ok line</pre>
  
  <p>So if I run: <code>vim test.txt</code>, I get the following error:</p>
  
  <pre>"test.txt" 3L, 39C
  Error detected while processing modelines:
  line    2:
  E518: Unknown option: bad
  Press ENTER or type command to continue</pre>
  
  <p>If I delete my <code>~/.vimrc</code>, the error disappears. But what is weird is that, even with an empty <code>~/.vimrc</code> file, the error appears.</p>
  
  <p>I understand that it's because the line starts with <code>vi:</code> that the error is created, but I don't understand why or how to fix this.</p>