What does != do in jade/pug?
<p>How does != work in jade code below..   <code>!= messages()</code></p>

<pre><code>extends layout

block content
 .spacer
 .container
  .row
   .col-lg-8.col-lg-offset-2.col-md-10.col-md-offset-1
    a(class='btn btn-tiny btn-primary' href='/manage/categories/add') Create Category
    h1= title
     small
      a(href='/manage/articles')  Manage Articles
    != messages()
    table(class='table table-striped')
     tr
      th Category Title
      th
     each category, i in categories
      tr
       td #{category.title}
       td 
        a(class="btn btn-tiny btn-default" href="/manage/categories/edit/#{category._id}") Edit
</code></pre>

<p>app.js</p>

<pre><code>app.use(require('connect-flash')());
app.use(function (req, res, next) {
  res.locals.messages = require('express-messages')(req, res);
  next();
});
</code></pre>