Using command line/batch to switch to/focus on app

This should work:

echo (new ActiveXObject("WScript.Shell")).AppActivate("app A"); > focus.js
cscript //nologo focus.js
del focus.js

try with sendKeys.bat :

call sendkeys.bat "Title A" ""

The first argument is the beginning of the title you want to switch to (if it is Some Title you can use only Some if it is unique enough). Second argument are empty double quotes. In general the script is used to send keys to a particular window. But if you left the second parameter empty (like "") it will not send any keys.