title: String comparison in TCL
body: <p>I have a variable <code>nodename = v445</code> and another variable <code>nodepatch=v445-sctpsv</code></p>
  
  <p>I want to compare as </p>
  
  <pre><code>if { $nodename == ???????} {
   }
  </code></pre>
  
  <p>so here I just want to compare only part before certain  <code>-</code>  the second variable could contain more than one - in name, so I just want to extract equivalent string to nodename to compare with.
  after string manipulation second part should come up like this:</p>
  
  <pre><code>if { $nodename == "v445"} {
   proceed } else { 
  }
  </code></pre>