Simply edit the, "User Configurable Settings" at the top of the script.  Use it to perform a variety of serial communications tasks such as automated configuration commands for a nearby repeater controller, etc.  I use it to keep the repeater controller's on-board clock accurate.  Since my node runs NTP and is configured to peer with several Stratum II time servers, it's clock is very accurate.  I have my repeater controller configured to announce the time on the hour and I want it to be as accurate as possible.  With the use of a daily cron job and my ser_cmd script, the correct time is sent to the controller at 0300 every morning.  This also serves to keep the repeater's clock in sync during daylight savings time switchover.  Very handy! :-)