title: How to replace particular character in string with tcl script?
body: <pre><code>set some_string "Name/is/ComplexSTRUCTUre" 
  </code></pre>
  
  <p>convert this string to,</p>
  
  <pre><code>some_string = "Name/is/ComplexSTR.CTUre" 
  </code></pre>
  
  <p>i.e replacing first <code>"U"</code> to <code>"."</code></p>