My immediate thought was '&' and signals. Following any command in Linux with an ampersand will cause it to run in the background (much like the bg command). The signals will allow you to control the script without having an interactive interface to it. As a comprehensive solution:
Create 2 scripts, we'll say the first is called jdataserver.pl, and the second is jdatalisten.pl
Have jdataserver.pl check for command-line options. If none are given, have it exec() jdatalisten.pl in the background (using bg or &, or is there a function in Perl?)
If the -i command-line option is given, have it check to see if jdatalisten.pl is running and if so send it a signal (there are user-defined ones on most OSes) that it knows how to catch.
If the -k command-line option is given, have it check to see if jdatalisten.pl is running and if so send it a SIGINT, SIGKILL, SIGQUIT, or whatever signal for it to catch.
Continue as desired for other functionality.
This could possibly also be accomplished with a single script, just having it check for its own existence in the processes (although it would have to exclude its own pid). [id://roger] also had some good resources posted above.