title: Incremental number in shell script on each loop
body: <pre><code>#!/bin/bash
  
  echo SCRIPT: $0
  echo "Enter Customer Order Ref (e.g. 100018)"
  read P_CUST_ORDER_REF
  echo "Enter DU Id (e.g. 100018)"
  read P_DU_ID
  
  P_ORDER_ID=${P_CUST_ORDER_REF}${P_DU_ID}
  
  
  #Loop through all XML files in the current directory
  for f in *.xml
  do
    #Increment P_CUST_ORDER_REF here
  done
  </code></pre>
  
  <p>Inside the for loop how can i increment P_CUST_ORDER_REF by 1 every time it loops</p>
  
  <pre><code>so it READs 10000028 uses it on first loop
  2nd 10000029
  3rd 10000030
  4th 10000031
  </code></pre>