title: Increment variable in Windows batch file
body: <p>How do you increment with Windows Batch? </p>
  
  <pre><code>set list=A B C D
  set /a "port=1010"
  
  for %%a in (%list%) do (
     echo %%a
     call :increaseby1
     echo %port%
  )
  :increaseby1
  set /a "port+=1"
  </code></pre>
  
  <p>My main goal here is to iterate over all list and call another batch file like this:</p>
  
  <p><em>for each list</em></p>
  
  <pre><code>dev_appserver.cmd -p [PORT+1] "A"
  </code></pre>
  
  <p>So this other batch would be called four times because the list is A B C and D. </p>