title: How to set global variables by command
body: <p>Thanks for so many fast response.<br>
  I used NodeJS(v4.3.2) and ExpressJs(v4.x) to build up website.<br>
  I used a lot AJAX and all AJAX url point to one static IP(AWS Server itself).<br>
  Because I would deploy to several servers, I don't want to change AJAX url separately.
  My idea is when I run "node bin/www" command line, Can I change it to "node bin/www 50.50.50.50(my AWS address)" and I can set all AJAX url to the right IP?<br>
  Is it possible or other alternative solustion?<br>
  Thanks</p>