title: How to use printf in GUI output
body: <p>i would like to output something in GUI but not sure how to do it.</p>
  
  <pre><code>our $output=$mw_rtframe-&gt;Scrolled('Text',-scrollbars=&gt;"se",-height=&gt;25,-width=&gt;150, -state=&gt;'disable', -wrap=&gt;'none')-&gt;pack(-side=&gt;'left',-anchor=&gt;'nw',-padx=&gt;5,-pady=&gt;5,-fill=&gt;'both',-expand=&gt;1);
  
  $output-&gt;configure(-state=&gt;'normal');
  $output -&gt; insert ('end', " line %02x not match with line %02x : %02x != %02x \n", $address+($i)*16,$address1+($i)*16,$line[$j],$line1[$j]);
  </code></pre>
  
  <p>But when output in my GUI it does not show the variable but something like this</p>
  
  <pre><code>8747687line %02x not match with line %02x : %02x != %02x
  </code></pre>
  
  <p>the output is work fine when using printf but cannot output in GUI. Any thing need to add to display in GUI? Thanks</p>