title: tmux open terminal failed: not a terminal
body: <p>I have a shell script that is enabled as service to start multiple shell scripts e.g.</p>
  
  <pre><code>service started script -&gt; script1, script2 ,script3 
  </code></pre>
  
  <p>script1 should open a program in a tmux window, and it does work just fine if I manually start the script via <code>./script1.sh</code>, however when started at boot via the service started script it does not with the above error:</p>
  
  <pre><code>open terminal failed: not a terminal
  </code></pre>
  
  <p>Why is this happening?</p>