title: set date to 90 days from current unix timestamp
body: <p>Hi i want to set my future_date variable to show a date that would be 90 days from today.</p>
  
  <pre><code>set $future_date ""
  #set $future_date to date in unixtime stamp 90 days from the current timestamp
  </code></pre>
  
  <p>Can i do that in tcl?</p>