title: What does putting a string in single quotes mean in bash?
body: <pre><code>VALUE1=123
  VALUE2=456
  S_ID=123456789
  G_ID=34634
  </code></pre>
  
  <p><code>/opt/customtools/custom_cmd -a -g $G_ID -m custom -c '=value9 $S_ID $VALUE1 $VALUE2'</code></p>
  
  <p>Never worked with bash scripting before and I'm looking through some code now and I've spotted this, and for some reason I can't find anywhere on the internet that describes what the end of this line does (the '=value9...part). Concatenate? Add? Please advise.  </p>