One of the disadvantages of using Nagios XI is that it does not allow you directly modify the configuration file, like /usr/local/nagios/etc/services/*.cfg, /usr/local/nagios/etc/hosts/*.cfg.
Well, let me make it more accurate. I should say that you are able to directly modify the configuration files, but your modifications will be overwritten by NagiosQL when you configured something on the Nagios XI web UI next time.
This restriction is really anoying, especially when you want to use a bash script to creat the services and hosts configuration files for a bunch of boxes that need to be monitored.