Bash scripting to determine between two terminals which one is in control.

Hello,

OS is Slackware 14.1

I am using bash scripts to communicate between two terminals and running scripts.

What command(s) can I use to tell which terminal is in control.

The goal is to let the other terminal, not in control, know that the other has executed the
loading of a configuration. Using this information it can then update its files two match
the one in control.

Thanks.

jefsa