title: Why is Vim and vi adding leadings characters instead of a blank line?
body: <p>On <a href="https://en.wikipedia.org/wiki/MacOS_High_Sierra" rel="nofollow noreferrer">macOS v10.13</a> (High Sierra), the <em>o</em> command adds a new line leading with a # instead of a blank line as expected.  This is off of a &quot;#include &lt;stdio.h&gt;&quot; line.  Other lines do similar things. How can I revert back to normal Vim (vi does the same thing)?</p>
  <p>I checked <em>:version</em> and all those rc files do not exist. The issue started after I tried to install an add on to do advanced syntax help.</p>