title: how to append a value to a variable in shell script
body: <p>I am getting a variable value from properties and I am able to access in sh file.
  but I am unable to append another value to that variable.</p>
  
  <p>Kindly suggest.</p>
  
  <pre><code>$ echo "Build ID from properties:"$BUILD_ID
  Build ID from properties: abcd_v6_c1
  
  $ echo " num----------------" build_${BUILD_ID}.zip
  .zip---------------- build_abcd_v6_c1
  </code></pre>
  
  <p>Kindly suggest how to append <strong>.zip</strong> value.</p>