title: Regex: Capture cases where character is not within spaces
body: <p>I am trying to write a <code>regex</code> in order to capture the cases \ lines in which a specific, single character (in my case the equal sign, <code>'='</code>) is not within spaces.</p>
  <p>Examples:</p>
  <pre><code>LABEL=SomeLabel    # -&gt; should be captured: spaces missing from both sides
  LABEL =SomeLabel   # -&gt; should be captured: space missing from the right
  LABEL= SomeLabel   # -&gt; should be captured: space missing from the left
  LABEL = SomeLabel  # -&gt; should **NOT** be captured: spaces in both sides
  </code></pre>
  <p>I am actually quite bad at regex so sharing my attempts does not make much sense.
  Plus, I have the feeling that this is a rather complex one...</p>